Fluoropolymer Emulsions with Perhalogenated Stabilizer for the Delivery of Hydrophobic Drugs

ABSTRACT

The present invention provides therapeutic formulations, including therapeutic nanoemulsions, and related methods for the in vivo delivery of hydrophobic compounds, including an important class of hydrophobic anesthetics. Formulations and methods of the invention include semifluorinated block copolymers and perhalogenated fluorous compounds, such as perfluorooctyl bromide or perfluorodecalin, capable of forming a stable nanoemulsion without the need of conventional lipid components that support bacterial and/or fungal growth (e.g., soybean oil and similar lipids). In certain embodiments, emulsion-based formulations are provided that are capable of formulating, delivering and releasing amounts of hydrophobic drugs effective for a range of clinical applications, including inducing and maintaining anesthesia in patients. In certain embodiments, emulsion-based formulations are provided that are capable of supporting controlled release, for example, over a range of rates useful for clinical applications including rapid and sustained release.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/984,639, filed Apr. 25, 2014, which is hereby incorporated byreference in its entirety to the extent not inconsistent herewith.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

Administration of hydrophobic drugs presents practical challenges due tothe limited water solubility of this class of pharmaceuticals.Accordingly, a primary focus of drug delivery research is development ofeffective approaches for the formulation and controlled delivery forthis class of important pharmaceutical agents. Nanoemulsions are aparticularly promising delivery vehicle for these applications giventheir intrinsic stability and potential to access useful pharmacokineticproperties for drug administration, absorption and targeting.

Nanoemulsions are composed of nanoscale droplets of one immiscibleliquid dispersed within another. In the context of many pharmaceuticalapplications, for example, the dispersed droplet phase of a nanoemulsionprovides a central oil core, stably dispersed in an aqueous phase, thatcan act as an effective reservoir for hydrophobic drugs. Nanomemulsionsfor delivery applications often incorporate one or more surfactantsand/or stabilizers to facilitate stabilization and improve drugsolubilization of the dispersed phase. As nonequilibrium systems,preparation of a nanoemulsion typically involves an input of energy, forexample, using a microfluidiser, high pressure homogeniser orultrasonicator.

Typical droplet sizes for nanoemulsions for the delivery ofpharmaceuticals are in the range of about 20-500 nm. The small dropletsize characteristic of nanoemulsions provides benefits supporting theiruse as vehicles for pharmaceutical delivery. First, the small dropletsize and lower surface tension between dispersed and aqueous phasesdecrease the rates of droplet agglomeration and precipitation processesso as to substantially limit the potential for phase separation viasedimentation, flocculation, coalescence and creaming. As a result,nanoemulsions are typically more kinetically stable than other types ofemulsions. Second, the nanosized dimensions of the droplets allow foreffective in vivo administration, for example via drug absorption fromthe gastrointestinal tract or penetration of the skin barrier. Third,the large interfacial area provided by the small size of the disperseddroplets allows for the potential to effectively control drug releaseover a clinical useful range. Accordingly, nanoemulsions havesignificant potential for providing rapid, sustained or targeteddelivery and release of hydrophobic drugs.

While emulsions have long been used for topical administration, recentresearch has been directed to development of emulsion-based deliverysystems effective for parenteral, inhalation and oral delivery.Phospholipid-stabilized soybean oil emulsions were the first approvedintravenous emulsion and have been used clinically as i.v. nutritionalsupplements for over 40 years. More recently, however, emulsions havebeen developed and employed widely in the clinic for the delivery ofcertain hydrophobic drugs, such as anesthetics, anti-inflammatory andanalgesic drugs, and also as blood substitutes.

Commercial propofol (i.e., Diprivan), for example, consists of anIntralipid® emulsion of the active agent 2,6-diisopropylphenol. Thelipid emulsion-based formulation of propofol is used extensively foranesthesiology practices for inducing and maintaining generalanesthesia. In addition, this emulsion-based formulation of propofol isused for procedural sedation and sedation in intensive care settings.Current lipid emulsion-based formulations of propofol are susceptible toproblems relating to the ability of their lipid component (e.g. soybeanoil) to support bacterial and fungal growth. To address the risk ofcontamination, for example, tubing and open vials of propofol must bereplaced every twelve hours for many clinical applications. In addition,infusion at high rates or as large bolus can result in lipidintolerance, which may contribute to propofol infusion syndrome, a rarebut serious complication that further limits use of lipid-basedemulsions of propofol in intensive care settings.

It will be appreciated from the foregoing that emulsion-based deliverysystems for the formulation and administration of hydrophobic drugs areneeded. Systems and formulations are needed that are capable ofproviding stable formulation of hydrophobic drugs exhibiting sparingsolubility in aqueous solutions, particularly, in concentrationssupporting a range of important clinical applications. Systems andformulations are needed exhibiting a high degree of biocompatibility,low toxicity and pharmacokinetic properties supporting controlleddelivery and targeting of hydrophobic drugs.

SUMMARY OF THE INVENTION

The present invention provides therapeutic formulations, includingtherapeutic nanoemulsions, and related methods for the in vivo deliveryof hydrophobic compounds, including an important class of hydrophobicanesthetics. Formulations and methods of the invention includesemifluorinated block copolymers and perhalogenated fluorous compounds,such as perfluorooctyl bromide or perfluorodecalin, capable of forming astable nanoemulsion without the need for conventional lipid componentsthat support bacterial and/or fungal growth (e.g., soybean oil andsimilar lipids). In certain embodiments, emulsion-based formulations areprovided that are capable of formulating, delivering and releasingamounts of hydrophobic drugs effective for a range of clinicalapplications, including inducing and maintaining anesthesia in patients.In certain embodiments, emulsion-based formulations are provided thatare capable of supporting controlled release, for example, over a rangeof rates useful for clinical applications including rapid and sustainedrelease.

In certain embodiments, nanoemulsion formulations of the presentinvention include linear semifluorinated block copolymers andperhalogenated fluorous compounds having compositions resulting inenhanced stability with respect to droplet size by decreasing the rateof Ostwald ripening, coagulation and/or phase separation processes.Therapeutic formulations of the present invention also provide a highdegree of versatility, as the amount and composition of thesemi-fluorinated block copolymer component (e.g., length and compositionof the hydrophilic block, length and composition of the fluorophilicblock, length and composition of the hydrophobic block, etc.) and theamount and chemical composition of the perhalogenated fluorous compoundsmay be selectively adjusted to: (i) enhance stability under deliveryconditions, (ii) optimize the kinetics of release of a hydrophobiccompound for a specific application (e.g. provide faster or slowerrelease rates), and (iii) enhance the overall formulation stability oftherapeutic nanoemulsions under storage conditions (e.g., increaseuseful shelf life).

In an embodiment, the present formulations comprise linearsemi-fluorinated block copolymers having hydrophilic, hydrophobic andfluorophilic blocks, and optionally a stabilizing additive, such as aperhalogenated fluorous compound, capable of generating an emulsion of aclinically effective amount of a hydrophobic compound, such as propofol,dispersed in an aqueous solution. Therapeutic formulations of thepresent invention include nanoemulsions comprising submicron droplets ofa hydrophobic compound dispersed in a continuous phase comprising anaqueous solution, such as an aqueous solution isotonic to blood plasma.In some embodiments, droplets of the hydrophobic compound of theemulsion are stabilized by the formation of supramolecular structures ofself-assembled semi-fluorinated block copolymer surfactants that reducethe interfacial tension of the hydrophobic compound at the dropletinterface with the continuous aqueous phase. In some embodiments, forexample, surfactant comprising linear semi-fluorinated block copolymershaving a hydrophilic block, hydrophobic block and a fluorophilic blockself-assemble upon emulsification to form supramolecular structuresdispersed in an aqueous continuous phase, thereby encapsulating andstabilizing significant quantities of the hydrophobic compound componentin a hydrophobic intermediate shell. For example, the hydrophobic blockof the semifluorinated block copolymers may form an intermediate shellof the supramolecular structure, thereby functioning as a molecularrecognition element for the hydrophobic compound. Optionally, thedispersed phase droplets of hydrophobic compound may also have astabilizing additive component for providing useful chemical andphysical properties.

In an aspect, the present invention provides emulsion-basedformulations, such as nanoemulsions. For example, in one embodiment, anemulsion of the invention is useful for delivery of a therapeutic agentcomprising a hydrophobic drug. Emulsions of this aspect are beneficial,for example, for delivering therapeutic agents comprising a hydrophobiccompound to a patient or subject, such as a therapeutic agent which isinsoluble or only sparingly soluble in aqueous solution. For example, insome embodiments, hydrophobic therapeutic agents which are soluble inaqueous solutions at concentrations or dosages less than a usefultherapeutic amount benefit from the emulsions of the invention, whichprovide for the ability to deliver a therapeutic or effective amount ofthe therapeutic agent to a patient or subject. In some embodiments, forexample, the nanoemulsions of the invention are useful for formulationand administration of hydrophobic anesthetic agents, such as propofol.

In an aspect, an emulsion of the invention comprises: an aqueoussolution, semi-fluorinated block copolymers, a therapeutic agentcomprising a hydrophobic compound and a perhalogenated fluorouscompound. In embodiments, for example, each of the semi-fluorinatedblock copolymers independently comprises a hydrophilic block, ahydrophobic block and a fluorophilic block, such as where thehydrophobic block of each of the semi-fluorinated block copolymers isprovided between the fluorophilic block and the hydrophilic block. Inexemplary embodiments, for example, the emulsion comprises a continuousphase and a dispersed phase, such as where the continuous phasecomprises the aqueous solution and the dispersed phase comprises thesemi-fluorinated block copolymers, the therapeutic agent and theperhalogenated fluorous compound.

In an embodiment of this aspect, the emulsion is a nanoemulsion, forexample, characterized by a dispersed phase comprising droplets havingcross sectional dimensions selected from the range of 20 nm to 1 micron,and optionally selected from the range of 100 nm to 1 micron. In anembodiment, the dispersed phase droplets comprise a hydrophobictherapeutic agent, the perhalogenated fluorous compound and optionallythe semi-fluorinated block copolymers, wherein said dropets have anaverage diameter less than or equal to 1000 nanometers, preferably forsome applications an average diameter less than or equal to 500nanometers, and more preferably for some applications an averagediameter less than or equal to 300 nanometers. Optionally, thetherapeutic formulation of this aspect of the present invention iscapable of delivery to a patient via parenteral administration, such asvia intravenous injection.

Emulsions of the invention for certain applications, optionally excludecertain substances or mixtures of substances from either or both thedispersed phase and the aqueous phase. Emulsions of the inventionoptionally include certain substances or mixtures in either or both thedispersed phase and the aqueous phase. For example, in some embodiments,certain substances or mixtures are either explicitly excluded from orincluded in the emulsion in order to control the physical properties,emulsion ripening rate, emulsion stability, composition, toxicity,biocompatibility, therapeutic effectiveness, therapeutic agent deliveryor release rate, immune or other physiological response or anycombination of these. In various embodiments, for example, an emulsiondoes not contain a vegetable oil component, such as a soy bean oilcomponent. In certain embodiments, for example, an emulsion does notsupport bacterial growth. In some embodiments, for example, an emulsiondoes not contain a lipid component. In some embodiments, for example, anemulsion does not contain a phospholipid component, such as an eggphospholipid component.

In embodiments, the composition and relative amounts of the componentsof the emulsions are selected so as to achieve a desired solubilizationamount of one or more hydrophobic therapeutic agents, such as aclinically or therapeutically effective amount. In embodiments, thecomposition and relative amounts of the components of the emulsions areselected so as to achieve a desired or controlled release rate, releasetiming or targeted delivery of one or more hydrophobic therapeuticagents.

In embodiments, emulsions of the invention comprise semi-fluorinatedblock copolymers. The structure, composition, size or concentration ofthe semi-fluorinated block copolymers and polymer block componentsthereof are optionally selected so as to provide certain properties tothe emulsion, such as physical properties, emulsion ripening rate,emulsion stability, therapeutic agent solubility, composition, toxicity,biocompatibility, therapeutic effectiveness, therapeutic agent deliveryrate or release rate, immune or other physiological response or anycombination of these. In an embodiment, the hydrophilic block andfluorophilic block as each independently polymer terminating blocks, forexample, wherein the hydrophobic block is an intermediate block provideddirectly or indirectly in between the hydrophilic block and fluorophilicblock.

In embodiments, for example, the semi-fluorinated block copolymers havea concentration selected from the range of 1 mg mL⁻¹ to 50 mg mL³¹ ¹,optionally for some applications selected from the range of 5 mg mL³¹ ¹to 50 mg mL³¹ ¹. In some embodiments, the semi-fluorinated blockcopolymers have a concentration selected from the range of 10 to 50 mgmL⁻¹. In embodiments, for example, each of the semi-fluorinated blockcopolymers independently has a molecular weight selected from the range100 Da to 20,000 Da, and optionally for some applications 1100 Da to14,000 Da.

In certain embodiments, the structure, composition or size of thehydrophilic block of the semi-fluorinated block copolymers are selectedso as to make stable emulsion-based formulations from a wide range ofhydrophobic therapeutic agents, such as hydrophobic anesthetics. Inexemplary embodiments, the hydrophilic block of each of thesemi-fluorinated block copolymers is a polymer terminating group. Inembodiments, the hydrophilic block is selected from the group consistingof a polyoxygenated polymer block, a polysaccharide block and a chitosanderivative block. In an embodiment, the hydrophilic block is apolyoxygenated block, such as a poly(ethylene glycol) block. Inexemplary embodiments, the hydrophilic block is a poly(ethylene glycol)block, for example, having a molecular weight selected from the range of500 g mol⁻¹ to 20,000 g mol⁻¹, otionally for some applications selectedfrom the range of 1000 g mol⁻¹ to 20,000 g mol⁻¹, optionally for someapplications selected from the range of 1000 g mol⁻¹ to 15,000 g mol⁻¹,and optionally for some applications selected from the range of 1000 gmol⁻¹ to 10,000 g mol⁻¹. In some embodiments, selection of thesize/molecular weight of the poly(ethylene glycol) block establishes therelease rate of a hydrophobic therapeutic agent and/or stability of thenanoemulsion with respect to ripening, coagulation and phase separationprocesses. In some embodiments, the hydrophilic block is directly linkedto the hydrophobic block.

In certain embodiments, the structure, composition or size of thefluorophilic block of the semi-fluorinated block copolymers are selectedso as to make stable emulsion-based formulations from a wide range ofhydrophobic therapeutic agents, such as hydrophobic anesthetics. Inexemplary embodiments, the fluorophilic block is a fluorocarbon moietyhaving at least 7 carbon-fluorine bonds, and optionally for someembodiments, at least 13 carbon-fluorine bonds, and optionally for someembodiments at least 21 carbon-fluorine bonds. For example, in oneembodiment, the fluorophilic block is a polymer terminating group. Inexemplary embodiments, each fluorophilic block is independently afluorocarbon moiety having between 3 to 50 carbon-fluorine bonds,optionally for some applications 13 to 50 carbon-fluorine bonds, andoptionally for some applications 3 to 31 carbon-fluorine bonds. In someembodiments, each fluorophilic block is independently a fluorinatedalkyl group having a length greater than or equal to 3 carbons andoptionally for some applications greater than or equal to 6 carbons, andoptionally for some embodiments greater than or equal to 10 carbons. Insome embodiments, the fluorophilic block is a fluorinated alkyl grouphaving a length of 3 to 20 carbons, optionally for some applications of3 to 15 carbons and optionally for some applications 6 to 15 carbons. Insome embodiments, for example, each fluorophilic block is independentlya perfluorinated alkyl group having a length of 3 to 15 carbons, andoptionally 3 to 8 carbons. In exemplary embodiments, the fluorophilicblock is directly linked to the hydrophobic block.

In some embodiments, the fluorophilic block, the hydrophilic block orboth are independently linked to the hydrophobic block via a linkingmoiety selected from the group consisting of an ether group, a carbamategroup, an amide group, an alkylene group, amino group or any combinationof these. In some emobodiments, for example, the fluorophilic block, thehydrophilic block or both are independently linked to the hydrophobicblock via a linking moiety having 1 to 10 carbons, such as a C₁-C₁₀ether group, a carbamate group, an amide group, an alkylene group oramino group.

In certain embodiments, the structure, composition or size of thehydrophobic block of the semi-fluorinated block copolymers are selectedso as to make stable emulsion-based formulations from a wide range ofhydrophobic therapeutic agents, such as hydrophobic anesthetics. Inembodiments, for example, the hydrophobic block is selected from thegroup consisting of a C₅-C₂₀ alkylene group, a poly (ε-caprolactone)block, a poly(lactic acid) block; a poly(propylene glycol) block; apoly(amino acid) block; a poly(ester) block and poly(lactic-co-glycolicacid). In some embodiments, the hydrophobic block is an unsubstitutedC₅-C₂₀ alkylene group, optionally an unsubstituted C₅-C₁₀ alkylenegroup. In some embodiments, the hydrophobic block is an saturated C₅-C₂₀alkylene group, optionally an saturated C₅-C₁₀ alkylene group. In anexemplary embodiment, the hydrophobic block is a group corresponding toan hexyl, heptyl, octyl, nonyl, decyl, undecyl or dodecyl group. In someembodiments, the hydrophobic block is an unsubstituted alkylene grouphaving at least 5 carbons, optionally for some applications at least 8carbons and optionally for some applications at least 10 carbons. In anexemplary embodiment, the hydrophobic block is derived from aphospholipid hydrophobic group, such as a glycerophospholipid. In anexemplary embodiment, the hydrophobic block is derived fromdistearoyl-glycero-phosphoethanolamine, such as1,2-distearoyl-S,N-glycero-3-phosphoethanolamine (DSPE).

In a specific embodiment, each of the semi-fluorinated block copolymersindependently has the formula (FX1):

where A is the hydrophilic block, B is the hydrophobic block and D isthe fluorophilic block; where L¹ and L² are each independently a linkinggroup; and where m is 0 or 1 and n is 0 or 1. For embodiments where m is0, L¹ is not present and A and B are directly bonded to one another. Forembodiments where n is 0, L² is not present and B and D are directlybonded to one another. In some embodiments, the semi-fluorinated blockcopolymers independently has the formula (FX1), wherein m is 0. In someembodiments, the semi-fluorinated block copolymers independently has theformula (FX1), wherein n is 0.

In certain embodiments, A is —(CH₂CH₂O)_(q)R¹, where R¹ is hydrogen,methyl, C₁-C₁₀ alkyl, C₃-C₁₀ cycloalkyl, C₅-C₁₀ aryl, C₅-C₁₀ heteroaryl,C₁-C₁₀ alkoxy or C₁-C₁₀ acyl and q is an integer selected from the rangeof 10 to 300, and optionally for some applications 20 to 100 andoptionally for some applications 20 to 50. In certain embodiments, B is—(CH₂)_(o)—, where o is an integer selected from the range of 5 to 30,and optionally for some applications 5 to 20, and optionally for someapplications 8 to 15. In certain embodiments, D is —(CF₂)_(p)R², whereR² is hydrogen, halo or C₁-C₅ alkyl and p is an integer selected fromthe range of 3 to 20, and optionally for some embodiments 3 to 15 andand optionally for some embodiments 6 to 15.

In a specific embodiment, each of the semi-fluorinated block copolymersindependently has the formula (FX2):

where q is an integer selected from the range of 10 to 300, o is aninteger selected from the range of 5 to 20, and p is an integer selectedfrom the range of 3 to 15; where R¹ is hydrogen, methyl, C₁-C₁₀ alkyl,C₃-C₁₀ cycloalkyl, C₅-C₁₀ aryl, C₅-C₁₀ heteroaryl, C₁-C₁₀ alkoxy orC₁-C₁₀ acyl; where R² is hydrogen, halo or C₁-0₅ alkyl; where each of L¹and L² is independently —(CH₂)_(e)—, —(CH₂)_(e)O(CH₂)_(f)—,—(CH₂)_(e)S(CH₂)_(f)—, —(CH₂)_(e)NR¹¹(CH₂)_(f)—,—(CH₂)_(e)OCONR¹²(CH₂)_(f)—, —(CH₂)_(e)CONR¹³(CH₂)_(f)—,—(CH₂)_(e)NR¹⁴COO(CH₂)_(f)—, —(CH₂)_(e)NR¹⁵CO(CH₂)_(f)— or—(CH₂)_(e)NR¹⁶CONR¹⁷(CH₂)_(f)—; where each of R¹¹-R¹⁷ is independentlyhydrogen, methyl, or C₁-C₅ alkyl; and where each of e and f isindependently an integer selected from the range of 0 to 5; and where mis 0 or 1 and n is 0 or 1. In a specific embodiment, thesemi-fluorinated block copolymers independently has the formula (FX2)and a halogen is selected from the group consisting of F, Cl and Br. Ina specific embodiment, when e is 0, the (CH₂)_(e) group is not presentand moieties adjacent to the (CH₂)_(e) group in the above describedstructures for L¹ and L² are directly bonded to one another. In aspecific embodiment, when f is 0, the (CH₂)_(f) group is not present andmoieties adjacent to the (CH₂)_(f) group in the above describedstructures for L¹ and L² are directly bonded to one another. In someembodiments, the semi-fluorinated block copolymers independently has theformula (FX7), wherein m is 0. In some embodiments, the semi-fluorinatedblock copolymers independently has the formula (FX7), wherein n is 0.

In some embodiments, the semi-fluorinated block copolymers independentlyhas the formula (FX2), wherein q is an integer selected from the rangeof 10 to 200, and optionally for some applications 10 to 100 andoptionally for some applications 10 to 50. In some embodiments, thesemi-fluorinated block copolymers independently has the formula (FX2),wherein o is an integer selected from the range of 5 to 16, andoptionally for some applications 8 to 16. In some embodiments, thesemi-fluorinated block copolymers independently has the formula (FX2),wherein p is an integer selected from the range of 5 to 15, andoptionally for some applications 8 to 15. In some embodiments, thesemi-fluorinated block copolymers independently has the formula (FX2),wherein R¹ is hydrogen, C₁-C₁₀ alkoxy or C₁-C₁₀ alkyl, and optionallymethyl or methoxy. In some embodiments, the semi-fluorinated blockcopolymers independently has the formula (FX2), wherein R² is hydrogenor halo, optionally F. In some embodiments, the semi-fluorinated blockcopolymers independently has the formula (FX2), wherein each of R¹¹-R¹⁷is independently hydrogen or C₁-C₅ alkyl, optionally methyl.

In a specific embodiment, L¹ is —O—. In a specific embodiment, L² is—OCH₂—. In a specific embodiment, each of the semi-fluorinated blockcopolymers independently has the formula (FX3A) or (FX3B):

In a specific embodiment, R¹ is —CH₃. In a specific embodiment, R² is—F.

In a specific embodiment, each of the semi-fluorinated block copolymersindependently has the formula (FX4) or (FX4B):

In an exemplary embodiment, each of the semi-fluorinated blockcopolymers independently has the formula (FX5A) or (FX5B):

In certain embodiments, the structure, composition, size orconcentration of the perhalogenated fluorous compound of emulsions ofthe invention is selected so as to make stable emulsion-basedformulations from a wide range of hydrophobic therapeutic agents, suchas hydrophobic anesthetics. In embodiments, the structure, composition,size or concentration of the perhalogenated fluorous compound areselected so as to provide certain properties to the emulsion, such asphysical properties, emulsion ripening rate, emulsion stability,therapeutic agent solubility, composition, toxicity, biocompatibility,therapeutic effectiveness, therapeutic agent delivery rate or releaserate, immune or other physiological response or any combination ofthese. For example, in one embodiment, the perhalogenated fluorouscompound is an emulsion stabilizing additive. In one embodiment, forexample, the perhalogenated fluorous compound is 5% to 30% by volume ofthe emulsion, optionally for some applications 5% to 20% by volume, andoptionally for some applications 5% to 10% by volume.

Selection of the perhalogenated fluorous compound, such as aperhalogenated fluorocarbon compound, having specific and well definedphysical and chemical properties is also important in the presentinvention for providing therapeutic formulations providing enhanceddelivery performance and stability, and for accessing therapeuticemulsions having clinically effective concentrations of hydrophobiccompounds. In some embodiments, for example, the perhalogenated fluorouscompound is provided that comprises a component of the dispersed dropletphase that controls the release rate of the hydrophobic compound fromthe droplets, thereby lowering the rate of droplet ripening processessuch as Ostwald ripening. The perhalogenated fluorous compound of thisaspect is useful for providing therapeutic emulsions, includingnanoemulsions, exhibiting stable droplets sizes and/or comprisingdroplets that undergo growth at rates sufficiently low to allow theiruse a therapeutic agents.

First, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, preferably exhibit highfluorophilicity. Exemplary perhalogenated fluorous compounds, such asperhalogenated fluorocarbon stabilizing additives, have a high affinityfor the fluorous block of the semifluorinated block copolymer, whichleads to a low interfacial tension with the block copolymer. For someapplications, the number of fluorine-carbon bonds is an importantparameter in selecting a perhalogenated fluorous compound, such as aperhalogenated fluorocarbon stabilizing additive, having anappropriately high fluorophilicity. Perhalogenated fluorous compoundshaving between 12 to 25 carbon- fluorine bonds are desirable for sometherapeutic formulations of the present invention. Alternatively, thenumber of carbon-fluorine bonds of the perhalogenated fluorous compoundmay be appropriately matched or otherwise related to the number ofcarbon-fluorine bonds of the fluorophilic block of the semi-fluorinatedblock copolymers.

Second, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, preferably exhibit low solubility inwater. Selection of perhalogenated fluorous compounds with low watersolubility is useful for avoiding degradation of the present therapeuticemulsion caused by over-ripening of fluorinated therapeutic containingparticles dispersed in a continuous aqueous phase. In an embodiment, theperhalogenated fluorous compound, such as a perhalogenated fluorocarbonstabilizing additive, has a solubility in water less than or equal to 20nanomolar. The particle ripening rate depends on the solubility of theadditive. Accordingly, use of perfluorooctyl bromide (abbreviated asPFOB), which has a solubility of 5 nM, provides for slow ripening. Inprinciple, however, an perhalogenated fluorous compound that is morewater-soluble, for example 20 nM, will also slow the ripening but not asmuch as fluoroderivatives that are less soluble.

Third, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, useful in the present therapeuticformulations are preferably chemically inert. Perfluorinated compounds,bromine substituted perfluorinated compounds and chlorine substitutedperfluorinated compounds provide useful chemically inert perhalogenatedfluorocarbon stabilizing additives in the present invention.

Fourth, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, useful in the present therapeuticformulations preferably are rapidly excreted, for example having acirculatory half-time (i.e., the time for the concentration ofperhalogenated fluorous compound to decrease by half in the circulation)less than two weeks.

Fifth, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, useful in the present therapeuticformulations preferably have a molecular weight selected over the rangeof 460 amu to 920 amu. Perhalogenated fluorous compounds havingmolecular weights below this range are typically susceptible to havingtoo high a vapor pressure, which can lead to lung emphysema and otherpulmonary complications. Perhalogenated fluorous compounds havingmolecular weights above this range typically exhibit excretion timesthat are undesirably long.

Sixth, perhalogenated fluorous compounds, such as perhalogenatedfluorocarbon stabilizing additives, useful in the present therapeuticformulations preferably are provided as high purity reagents. Benefitsof the use of high purity reagents are that no toxicity, carcinogenic,mutagenic, teratogenic effects, or immunological reactions, have beenreported for many fluorocarbons when provided in a sufficiently pureform and chosen within an appropriate molecular weight range.

A variety of perhalogenated fluorous compounds are useful with theemulsions of the invention. In one embodiment, the perhalogenatedfluorous compound has 12 to 25 carbon-fluorine bonds, optionally forsome applications 15 to 20 carbon-fluorine bonds. In an exemplaryembodiment, the perhalogenated fluorous compound is a substituted orunsubstituted fluorocarbon having a length of 4 to 20 carbons, andoptionally for some applications 5 to 15 carbons, and optionally forsome applications 5 to 10 carbons. In embodiments, the perhalogenatedfluorous compound comprises a perfluorocarbon. In embodiments, theperhalogenated fluorous compound comprises a perfluorocarbon in whichone or more fluorine atoms are substituted with Cl, Br or I, optionallyin which one or more fluorine atoms are substituted with Cl or Br. Invarious embodiments, the substituted or unsubstituted fluorocarbon islinear, branched or cyclic. In embodiments, the substituted orunsubstituted fluorocarbon is a substituted or unsubstituted C₄-C₂₀fluoroalkane, optionally for some applications C₄-C₁₅ fluoroalkane, andoptionally for some applications C₄-C₁₀ fluoroalkane.

In embodiments, for example, the perhalogenated fluorous compound has asolubility in water less than or equal to 20 nanomolar. In embodiments,for example, the perhalogenated fluorous compound has a molecular weightselected over the range of 460 amu to 920 amu. In exemplary embodiments,the perhalogenated fluorous compound is selected from the groupconsisting of: a perfluorocarbon; a bromine substituted perfluorocarbon;a chlorine substituted perfluorocarbon; and a bromine and chlorinesubstituted perfluorocarbon.

A variety of specific perhalogenated fluorous compounds are useful withthe emulsions of the invention. In specific embodiments, for example,the perhalogenated fluorous compound is selected from the groupconsisting of perfluorooctyl bromide, perfluorononyl bromide,perfluorodecyl bromide, perfluorodecalin, perfluorodichlorooctane,bis-perfluorobutyl ethylene and perfluoro(methyldecalin). Inembodiments, the perhalogenated fluorous compound is perfluorooctylbromide or perfluorodecalin. In embodiments, the perhalogenated fluorouscompound is perfluorooctyl bromide.

Optionally, emulsions of the invention further comprise one or moreadditional perhalogenated fluorous compounds including, for example, anyof the perhalogenated fluorous compounds disclosed herein. Optionally,emulsions of the invention further comprise one or more additionalfluorocarbon stabilizing additives including, for example, any of thefluorocarbon stabilizing additives herein. Emulsions of the inventioninclude formulations comprising two or more of any of the perhalogenatedfluorous compounds disclosed herein, for example, the combination ofperfluorooctyl bromide and perfluorodecalin.

A variety of therapeutic agents are useful with the emulsions of theinvention. In certain embodiments, the structure, composition, size orconcentration of the therapeutic agent is selected so as to make astable emulsion-based formulation. In embodiments, the structure,composition, size or concentration of the therapeutic agent are selectedso as to provide certain properties to the emulsion, such as physicalproperties, emulsion ripening rate, emulsion stability, therapeuticagent solubility, composition, toxicity, biocompatibility, therapeuticeffectiveness, therapeutic agent delivery rate or release rate, immuneor other physiological response or any combination of these. In anembodiment, for example, the therapeutic agent has a concentration of atleast 0.2 mg mL⁻¹ in the emulsion, and optionally for some embodimentsat least 1 mg mL⁻¹. In an embodiment, the therapeutic agent has aconcentration selected from the range of 0.2 mg mL⁻¹ to 30 mg mL⁻¹ inthe emulsion.

In certain embodiments, the therapeutic agent is a hydrophobic compound.Use of hydrophobic therapeutic agents is beneficial as a variety ofhydrophobic therapeutic agents exhibit reduced toxicity, increasedtherapeutic effectiveness or smaller required therapeutic dosages ascompared to some non-hydrophobic therapeutic agents. In addition,therapeutic agents for a desired clinical application may only beavailable as a hydrophobic compound. In embodiments, emulsions of theinvention are, thus, particularly useful for providing a therapeuticallydeliverable quantity of a hydrophobic therapeutic agent in order toachieve a desired clinical outcome, such as anesthesia. In a specificembodiment, the hydrophobic compound has a concentration of 0.2 to 50 mgmL⁻¹, optionally for some applications a concentration of 1 to 50 mgmL⁻¹. In an embodiment, for example, the hydrophobic compound ischaracterized by a solubility in water of equal to or less than 5 mM,optionally for some applications equal to or less than 1 mM andoptionally equal to or less than 0.7 mM. For reference, the solubilityof propofol in water is 0.124 mg/ml corresponding to 0.696 mM.

In a specific embodiment, the hydrophobic compound is noncovalentlyassociated with the hydrophobic block, the fluorophilic block or boththe hydrophobic block and the fluorophilic block of the semi-fluorinatedblock copolymers. For example, in embodiments, the hydrophobic compoundis dissolved or solvated by a hydrophobic block, a fluorophilic block orboth, such that the hydrophobic compound is suspended or otherwisedeliverable by an emulsion of the invention.

A variety of hydrophobic compounds are useful with the emulsions of theinvention. In a specific embodiment, the hydrophobic compound is ahydrophobic drug. In a specific embodiment, the hydrophobic compound isan anesthetic drug. In embodiments, the hydrophobic compound is asubstituted or unsubstituted aromatic compound or a substituted orunsubstituted heteroaromatic compound. In a specific embodiment, forexample, the hydrophobic compound is a neurosteroid drug. In exemplaryembodiments, the anesthetic drug is propofol or alfaxalone. Optionally,the anesthetic drug has a concentration of 5 mg mL⁻¹ to 50 mg mL⁻¹ inthe emulsion. Optionally, the anesthetic drug is propofol provided at aconcentration of 5 mg mL⁻¹ to 50 mg mL⁻¹ in the emulsion. In anembodiment, said droplets do not undergo an appreciable change in size(e.g., 10% or greater change) over a time period of 1 month or more

In a specific embodiment, the hydrophobic compound is not a fluorinatedanesthetic compound. In a specific embodiment, the hydrophobic compoundis not sevoflurane. In a specific embodiment, the hydrophobic compoundis not isoflurane. In a specific embodiment, the hydrophobic compound isnot desflurane. In a specific embodiment, the hydrophobic compound isnot enflurane. In a specific embodiment, the hydrophobic compound is notmethoxyflurane.

As described above, the present invention provides emulsions, such asemulsions comprising a continuous phase and a dispersed phase. Incertain embodiments, the aqueous solution of the continuous phasecomprises a saline solution. In embodiments, for example, the aqueoussolution of the continuous phase is isotonic to blood plasma. In anembodiment, the dispersed phase comprises a plurality of dropletsdispersed in the continuous phase. In embodiments, for example, thedroplets dispersed in the continuous phase comprise self-assembledsupramolecular structures. Various emulsion embodiments do not includemicelle-based solutions, but instead comprise droplets of the dispersedphase suspended in the continuous phase.

In some embodiments, for example, the droplets have a hydrophilicexterior shell comprising the hydrophilic blocks of the semi-fluorinatedblock copolymers. In some embodiments, for example, the droplets have ahydrophobic intermediate shell comprising the hydrophobic blocks of thesemi-fluorinated block copolymers. In some embodiments, for example, thedroplets have a fluorophilic core. In exemplary embodiments, forexample, the hydrophobic compound is noncovalently associated with thehydrophobic intermediate shell.

In a specific embodiment, an exemplary emulsion of the inventioncomprises the hydrophobic compound at a concentration of 0.2 to 50 mgmL⁻¹, the perhalogenated fluorous compound is 5% to 20% by volume of theemulsion; and the semi-fluorinated block copolymers at a concentrationselected from the range of 10 to 50 mg mL⁻¹. In a specific embodiment,an exemplary emulsion of the invention comprises the hydrophobiccompound at a concentration of 0.2 to 50 mg mL⁻¹; and thesemi-fluorinated block copolymers at a concentration selected from therange of 10 to 50 mg mL⁻¹. Exemplary emulsion embodiments are useful foradministration to a patient in need thereof via intraveneous injection.

Emulsions of embodiments of the invention are stable and possess a shelflife such that the emulsions do not quickly settle into two or morephases and thus are suitable for administration to a patient or subjectat a time period after the emulsion is prepared or manufactured, such asa time period greater than 1 day or greater than 1 month. In anexemplary embodiment, the droplets do not undergo an appreciable changein size over a period of 1 day to 4 weeks. In embodiments, for example,an appreciable change in size is a change that is greater than or equalto a 10% increase.

For certain embodiments, an emulsion of the invention comprises ananoemulsion. For example, in some embodiments, the emulsion comprisesdroplets having an average diameter selected from the range of 1 nm to500 nm. For example, in some embodiments, the emulsion comprisesdroplets having an average diameter less than 1000 nm. In someembodiments, the emulsion comprises droplets having an average diameterless than 400 nm. For some embodiments, the emulsion does not comprisemicelles. For some embodiments, the emulsion does not comprise vesicles.In certain embodiments, the emulsion is not a microemulsion. For someembodiments, the emulsion comprises a supramolecular structure. Forother embodiments, the emulsion does not comprise a supramolecularstructure.

In another aspect, the present invention provides methods. A method ofthis aspect comprises a method of delivering a therapeutic agent to apatient in need thereof. In an embodiment, such a method comprises, forexample, the steps of: providing an emulsion comprising: an aqueoussolution; semi-fluorinated block copolymers; a therapeutic agentcomprising a hydrophobic compound; and a perhalogenated fluorouscompound; wherein each of the semi-fluorinated block copolymersindependently comprises a hydrophilic block, a hydrophobic block and afluorophilic block; wherein the hydrophobic block of each of thesemi-fluorinated block copolymers is provided between the fluorophilicblock and the hydrophilic block; wherein the emulsion comprises acontinuous phase and a dispersed phase, wherein the continuous phasecomprises the aqueous solution and the dispersed phase comprises thesemi-fluorinated block copolymers, the therapeutic agent and theperhalogenated fluorous compound; and administering the emulsion to thepatient, wherein the therapeutic agent is released from the emulsion,thereby delivering the therapeutic agent to the patient in need thereof.

In exemplary embodiments, an emulsion administered to a patientcomprises any of the emulsions described previously herein. In aspecific embodiment, an emulsion administered to a patient is ananoemulsion. In a specific embodiment, the hydrophobic compoundadministered to a patient is a hydrophobic drug, such as an anestheticdrug, for example propofol.

In exemplary embodiments of methods of this aspect, the step ofadministering the emulsion provides for controlled release of thehydrophobic drug from the emulsion. Optionally, the step ofadministering the emulsion is carried out via intraveneous injection. Ina specific embodiment, a volume of the emulsion less than or equal to500 mL is administered to the patient. In exemplary embodiments, avolume of the emulsion selected from the range 0.1 mL to 500 mL isadministered to the patient. In a specific embodiment, the emulsion isdelivered to the patient at a rate less than or equal to 100 mL perminute. In exemplary embodiments, the emulsion is delivered to thepatient at a rate selected from the range of 0.01 to 10 mL per minute.

In a further aspect, provided are methods of making emulsions. Inexemplary embodiments, the emulsion is a nanoemulsion. An exemplarymethod of this aspect comprises the steps of: providing a therapeuticformulation comprising: an aqueous solution; semi-fluorinated blockcopolymers; wherein each of the semi-fluorinated block copolymersindependently comprises a hydrophilic block, a hydrophobic block and afluorophilic block; wherein the hydrophobic block of each of thesemi-fluorinated block copolymers is provided between the fluorophilicblock and the hydrophilic block; a therapeutic agent comprising ahydrophobic compound; and a perhalogenated fluorous compound; andemulsifying the therapeutic formulation, thereby making an emulsioncomprising a continuous phase and a dispersed phase, wherein thecontinuous phase comprises the aqueous solution and the dispersed phasecomprises the semi-fluorinated block copolymers, the therapeutic agentand the perhalogenated fluorous compound.

In certain embodiments of methods of this aspect, the step ofemulsifying the therapeutic formulation comprises the steps of: addingthe hydrophobic compound and the perhalogenated fluorous compound to theaqueous solution having the semi-fluorinated block copolymers therein,thereby generating a mixture; and homogenizing the mixture, therebygenerating the emulsion. In exemplary embodiments, methods of thisaspect further comprise a step of lowering a temperature of the mixtureduring the step of homogenizing the mixture. In embodiments, forexample, the step of homogenizing the mixture is carried out using alower energy mixer, a microfluidizer or both. Low-energy mixers areknown in the art, such as described in AlChE J., 57:27-39. doi:10.1002/aic.12253.

Without wishing to be bound by any particular theory, there may bediscussion herein of beliefs or understandings of underlying principlesrelating to the devices and methods disclosed herein. It is recognizedthat regardless of the ultimate correctness of any mechanisticexplanation or hypothesis, an embodiment of the invention cannonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. provides a schematic illustration of the formation of dispersedphase droplets in an emulsion.

FIG. 2. provides a plot showing the mean droplet diameter (nm) for theemulsions corresponding to Formulations 1, 2 and 3 evaluated as afunction of time (days).

FIG. 3. provides plots of time to Loss of Righting Reflex (LORR) (s) asa function of dose (mg/kg).

FIG. 4. provides plots of time to Time to Return of Righting Reflex (s)as a function of dose (mg/kg).

FIG. 5. provides a plot showing the average particle size (nm) for theemulsions corresponding to formulations B8 and L3 were evaluated as afunction of time (days).

FIG. 6. provides a plot showing the average particle size (nm) for theemulsions corresponding to formulations M1H10F8/PFOB, M5diH10, andLipoid E80 were evaluated as a function of time (days).

FIG. 7. provides plots of time to Time to Return of Righting Reflex (s)as a function of the logarithm of the dose (mg/kg).

FIG. 8. provides plots of time to Time to Return of Righting Reflex (s)as a function of the logarithm of the dose (mg/kg).

FIG. 9. provides plots of time to Time to Return of Righting Reflex (s)as a function of the logarithm of the dose (mg/kg).

FIG. 10. provides plots of time to Time to Return of Righting Reflex (s)vs Intralipid® dose (mL/kg).

STATEMENTS REGARDING CHEMICAL COMPOUNDS AND NOMENCLATURE

In an embodiment, a composition or compound of the invention is isolatedor purified. In an embodiment, an isolated or purified compound is atleast partially isolated or purified as would be understood in the art.In an embodiment, the composition or compound of the invention has achemical purity of 95%, optionally for some applications 99%, optionallyfor some applications 99.9%, optionally for some applications 99.99%,and optionally for some applications 99.999% pure.

Many of the molecules disclosed herein contain one or more ionizablegroups. Ionizable groups include groups from which a proton can beremoved (e.g., —COON) or added (e.g., amines) and groups which can bequaternized (e.g., amines). All possible ionic forms of such moleculesand salts thereof are intended to be included individually in thedisclosure herein. With regard to salts of the compounds herein, one ofordinary skill in the art can select from among a wide variety ofavailable counterions that are appropriate for preparation of salts ofthis invention for a given application. In specific applications, theselection of a given anion or cation for preparation of a salt canresult in increased or decreased solubility of that salt.

As used throughout the present description, the expression “a groupcorresponding to” an indicated species expressly includes a radical(including a monovalent, divalent and trivalent radical) derived fromthat species.

The compounds of this invention and used with the methods or emulsionsof the invention can contain one or more chiral centers. Accordingly,this invention is intended to include racemic mixtures, diasteromers,enantiomers, tautomers and mixtures enriched in one or morestereoisomer. The scope of the invention as described and claimedencompasses the racemic forms of the compounds as well as the individualenantiomers and non-racemic mixtures thereof.

As used herein, the term “group” may refer to a functional group of achemical compound. Groups of the present compounds refer to an atom or acollection of atoms that are a part of the compound. Groups of thepresent invention may be attached to other atoms of the compound via oneor more covalent bonds. Groups may also be characterized with respect totheir valence state. The present invention includes groups characterizedas monovalent, divalent, trivalent, etc. valence states.

As used herein, the term “substituted” refers to a compound wherein ahydrogen is replaced by another functional group.

As is customary and well known in the art, hydrogen atoms in formulas(FX1)-(FX5) are not always explicitly shown, for example, hydrogen atomsbonded to the carbon atoms of aromatic, heteroaromatic, and alicyclicrings are not always explicitly shown in formulas (FX1)-(FX5). Thestructures provided herein, for example in the context of thedescription of formulas (FX1)-(FX5), are intended to convey to one ofreasonable skill in the art the chemical composition of compounds of themethods and compositions of the invention, and as will be understood byone of skill in the art, the structures provided do not indicate thespecific positions of atoms and bond angles between atoms of thesecompounds.

As used herein, the terms “alkylene” and “alkylene group” are usedsynonymously and refer to a divalent group derived from an alkyl groupas defined herein. The invention includes compounds having one or morealkylene groups. Alkylene groups in some compounds function as attachingand/or spacer groups. Compounds of the invention may have substitutedand/or unsubstituted C₁-C₂₀ alkylene, C₁-C₁₀ alkylene and C₁-C₅ alkylenegroups.

As used herein, the terms “cycloalkylene” and “cycloalkylene group” areused synonymously and refer to a divalent group derived from acycloalkyl group as defined herein. The invention includes compoundshaving one or more cycloalkylene groups. Cycloalkyl groups in somecompounds function as attaching and/or spacer groups. Compounds of theinvention may have substituted and/or unsubstituted C₃-C₂₀cycloalkylene, C₃-C₁₀ cycloalkylene and C₃-C₅ cycloalkylene groups.

As used herein, the terms “arylene” and “arylene group” are usedsynonymously and refer to a divalent group derived from an aryl group asdefined herein. The invention includes compounds having one or morearylene groups. In some embodiments, an arylene is a divalent groupderived from an aryl group by removal of hydrogen atoms from twointra-ring carbon atoms of an aromatic ring of the aryl group. Arylenegroups in some compounds function as attaching and/or spacer groups.Arylene groups in some compounds function as chromophore, fluorophore,aromatic antenna, dye and/or imaging groups. Compounds of the inventioninclude substituted and/or unsubstituted C₃-C₃₀ arylene, C₃-C₂₀ arylene,C₃-C₁₀ arylene and C₁-C₅ arylene groups.

As used herein, the terms “heteroarylene” and “heteroarylene group” areused synonymously and refer to a divalent group derived from aheteroaryl group as defined herein. The invention includes compoundshaving one or more heteroarylene groups. In some embodiments, aheteroarylene is a divalent group derived from a heteroaryl group byremoval of hydrogen atoms from two intra-ring carbon atoms or intra-ringnitrogen atoms of a heteroaromatic or aromatic ring of the heteroarylgroup. Heteroarylene groups in some compounds function as attachingand/or spacer groups. Heteroarylene groups in some compounds function aschromophore, aromatic antenna, fluorophore, dye and/or imaging groups.Compounds of the invention include substituted and/or unsubstitutedC₃-C₃₀ heteroarylene, C₃-C₂₀ heteroarylene, C₁-C₁₀ heteroarylene andC₃-C₅ heteroarylene groups.

As used herein, the terms “alkenylene” and “alkenylene group” are usedsynonymously and refer to a divalent group derived from an alkenyl groupas defined herein. The invention includes compounds having one or morealkenylene groups. Alkenylene groups in some compounds function asattaching and/or spacer groups. Compounds of the invention includesubstituted and/or unsubstituted C₂-C₂₀ alkenylene, C₂-C₁₀ alkenyleneand C₂-C₅ alkenylene groups.

As used herein, the terms “cylcoalkenylene” and “cylcoalkenylene group”are used synonymously and refer to a divalent group derived from acylcoalkenyl group as defined herein. The invention includes compoundshaving one or more cylcoalkenylene groups. Cycloalkenylene groups insome compounds function as attaching and/or spacer groups. Compounds ofthe invention include substituted and/or unsubstituted C₃-C₂₀cylcoalkenylene, C₃-C₁₀ cylcoalkenylene and C₃-C₅ cylcoalkenylenegroups.

As used herein, the terms “alkynylene” and “alkynylene group” are usedsynonymously and refer to a divalent group derived from an alkynyl groupas defined herein. The invention includes compounds having one or morealkynylene groups. Alkynylene groups in some compounds function asattaching and/or spacer groups. Compounds of the invention includesubstituted and/or unsubstituted C₂-C₂₀ alkynylene, C₂-C₁₀ alkynyleneand C₂-C₅ alkynylene groups.

As used herein, the term “halo” refers to a halogen group such as afluoro (—F), chloro (—Cl), bromo (—Br), iodo (—I) or astato (—At).

The term “heterocyclic” refers to ring structures containing at leastone other kind of atom, in addition to carbon, in the ring. Examples ofsuch heteroatoms include nitrogen, oxygen and sulfur. Heterocyclic ringsinclude heterocyclic alicyclic rings and heterocyclic aromatic rings.Examples of heterocyclic rings include, but are not limited to,pyrrolidinyl, piperidyl, imidazolidinyl, tetrahydrofuryl,tetrahydrothienyl, furyl, thienyl, pyridyl, quinolyl, isoquinolyl,pyridazinyl, pyrazinyl, indolyl, imidazolyl, oxazolyl, thiazolyl,pyrazolyl, pyridinyl, benzoxadiazolyl, benzothiadiazolyl, triazolyl andtetrazolyl groups. Atoms of heterocyclic rings can be bonded to a widerange of other atoms and functional groups, for example, provided assubstituents.

The term “carbocyclic” refers to ring structures containing only carbonatoms in the ring. Carbon atoms of carbocyclic rings can be bonded to awide range of other atoms and functional groups, for example, providedas substituents.

The term “alicyclic ring” refers to a ring, or plurality of fused rings,that is not an aromatic ring. Alicyclic rings include both carbocyclicand heterocyclic rings.

The term “aromatic ring” refers to a ring, or a plurality of fusedrings, that includes at least one aromatic ring group. The term aromaticring includes aromatic rings comprising carbon, hydrogen andheteroatoms. Aromatic ring includes carbocyclic and heterocyclicaromatic rings. Aromatic rings are components of aryl groups.

The term “fused ring” or “fused ring structure” refers to a plurality ofalicyclic and/or aromatic rings provided in a fused ring configuration,such as fused rings that share at least two intra ring carbon atomsand/or heteroatoms.

As used herein, the term “alkoxyalkyl” refers to a substituent of theformula alkyl-O-alkyl.

As used herein, the term “polyhydroxyalkyl” refers to a substituenthaving from 2 to 12 carbon atoms and from 2 to 5 hydroxyl groups, suchas the 2,3-dihydroxypropyl, 2,3,4-tri hydroxybutyl or2,3,4,5-tetrahydroxypentyl residue.

As used herein, the term “polyalkoxyalkyl” refers to a substituent ofthe formula alkyl-(alkoxy)_(n)-alkoxy wherein n is an integer from 1 to10, preferably 1 to 4, and more preferably for some embodiments 1 to 3.

Amino acids include glycine, alanine, valine, leucine, isoleucine,methionine, proline, phenylalanine, tryptophan, asparagine, glutamine,glycine, serine, threonine, serine, rhreonine, asparagine, glutamine,tyrosine, cysteine, lysine, arginine, histidine, aspartic acid andglutamic acid. As used herein, reference to “a side chain residue of anatural a-amino acid” specifically includes the side chains of theabove-referenced amino acids.

Alkyl groups include straight-chain, branched and cyclic alkyl groups.Alkyl groups include those having from 1 to 30 carbon atoms. Alkylgroups include small alkyl groups having 1 to 3 carbon atoms. Alkylgroups include medium length alkyl groups having from 4-10 carbon atoms.Alkyl groups include long alkyl groups having more than 10 carbon atoms,particularly those having 10-30 carbon atoms. The term cycloalkylspecifically refers to an alky group having a ring structure such asring structure comprising 3-30 carbon atoms, optionally 3-20 carbonatoms and optionally 2-10 carbon atoms, including an alkyl group havingone or more rings. Cycloalkyl groups include those having a 3-, 4-, 5-,6-, 7-, 8-, 9- or 10-member carbon ring(s) and particularly those havinga 3-, 4-, 5-, 6-, or 7-member ring(s). The carbon rings in cycloalkylgroups can also carry alkyl groups. Cycloalkyl groups can includebicyclic and tricycloalkyl groups. Alkyl groups are optionallysubstituted. Substituted alkyl groups include among others those whichare substituted with aryl groups, which in turn can be optionallysubstituted. Specific alkyl groups include methyl, ethyl, n-propyl,iso-propyl, cyclopropyl, n-butyl, s-butyl, t-butyl, cyclobutyl,n-pentyl, branched-pentyl, cyclopentyl, n-hexyl, branched hexyl, andcyclohexyl groups, all of which are optionally substituted. Substitutedalkyl groups include fully halogenated or semihalogenated alkyl groups,such as alkyl groups having one or more hydrogens replaced with one ormore fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms.Substituted alkyl groups include fully fluorinated or semifluorinatedalkyl groups, such as alkyl groups having one or more hydrogens replacedwith one or more fluorine atoms. An alkoxy group is an alkyl group thathas been modified by linkage to oxygen and can be represented by theformula R—O and can also be referred to as an alkyl ether group.Examples of alkoxy groups include, but are not limited to, methoxy,ethoxy, propoxy, butoxy and heptoxy. Alkoxy groups include substitutedalkoxy groups wherein the alky portion of the groups is substituted asprovided herein in connection with the description of alkyl groups. Asused herein MeO— refers to CH₃O—.

Alkenyl groups include straight-chain, branched and cyclic alkenylgroups. Alkenyl groups include those having 1, 2 or more double bondsand those in which two or more of the double bonds are conjugated doublebonds. Alkenyl groups include those having from 2 to 20 carbon atoms.Alkenyl groups include small alkenyl groups having 2 to 3 carbon atoms.Alkenyl groups include medium length alkenyl groups having from 4-10carbon atoms. Alkenyl groups include long alkenyl groups having morethan 10 carbon atoms, particularly those having 10-20 carbon atoms.Cycloalkenyl groups include those in which a double bond is in the ringor in an alkenyl group attached to a ring. The term cycloalkenylspecifically refers to an alkenyl group having a ring structure,including an alkenyl group having a 3-, 4-, 5-, 6-, 7-, 8-, 9- or10-member carbon ring(s) and particularly those having a 3-, 4-, 5-, 6-or 7-member ring(s). The carbon rings in cycloalkenylgroups can alsocarry alkyl groups. Cycloalkenylgroups can include bicyclic andtricyclic alkenyl groups. Alkenyl groups are optionally substituted.Substituted alkenyl groups include among others those which aresubstituted with alkyl or aryl groups, which groups in turn can beoptionally substituted. Specific alkenyl groups include ethenyl,prop-1-enyl, prop-2-enyl, cycloprop-1-enyl, but-1-enyl, but-2-enyl,cyclobut-1-enyl, cyclobut-2-enyl, pent-1-enyl, pent-2-enyl, branchedpentenyl, cyclopent-1-enyl, hex-1-enyl, branched hexenyl, cyclohexenyl,all of which are optionally substituted. Substituted alkenyl groupsinclude fully halogenated or semihalogenated alkenyl groups, such asalkenyl groups having one or more hydrogens replaced with one or morefluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms.Substituted alkenyl groups include fully fluorinated or semifluorinatedalkenyl groups, such as alkenyl groups having one or more hydrogen atomsreplaced with one or more fluorine atoms.

Aryl groups include groups having one or more 5-, 6- or 7-memberaromatic rings, including heterocyclic aromatic rings. The termheteroaryl specifically refers to aryl groups having at least one 5-, 6-or 7-member heterocyclic aromatic rings. Aryl groups can contain one ormore fused aromatic rings, including one or more fused heteroaromaticrings, and/or a combination of one or more aromatic rings and one ormore nonaromatic rings that may be fused or linked via covalent bonds.Heterocyclic aromatic rings can include one or more N, O, or S atoms inthe ring. Heterocyclic aromatic rings can include those with one, two orthree N atoms, those with one or two O atoms, and those with one or twoS atoms, or combinations of one or two or three N, O or S atoms. Arylgroups are optionally substituted. Substituted aryl groups include amongothers those which are substituted with alkyl or alkenyl groups, whichgroups in turn can be optionally substituted. Specific aryl groupsinclude phenyl, biphenyl groups, pyrrolidinyl, imidazolidinyl,tetrahydrofuryl, tetrahydrothienyl, furyl, thienyl, pyridyl, quinolyl,isoquinolyl, pyridazinyl, pyrazinyl, indolyl, imidazolyl, oxazolyl,thiazolyl, pyrazolyl, pyridinyl, benzoxadiazolyl, benzothiadiazolyl, andnaphthyl groups, all of which are optionally substituted. Substitutedaryl groups include fully halogenated or semihalogenated aryl groups,such as aryl groups having one or more hydrogens replaced with one ormore fluorine atoms, chlorine atoms, bromine atoms and/or iodine atoms.Substituted aryl groups include fully fluorinated or semifluorinatedaryl groups, such as aryl groups having one or more hydrogens replacedwith one or more fluorine atoms. Aryl groups include, but are notlimited to, aromatic group-containing or heterocylic aromaticgroup-containing groups corresponding to any one of the following:benzene, naphthalene, naphthoquinone, diphenylmethane, fluorene,anthracene, anthraquinone, phenanthrene, tetracene, tetracenedione,pyridine, quinoline, isoquinoline, indoles, isoindole, pyrrole,imidazole, oxazole, thiazole, pyrazole, pyrazine, pyrimidine, purine,benzimidazole, furans, benzofuran, dibenzofuran, carbazole, acridine,acridone, phenanthridine, thiophene, benzothiophene, dibenzothiophene,xanthene, xanthone, flavone, coumarin, azulene or anthracycline. As usedherein, a group corresponding to the groups listed above expresslyincludes an aromatic or heterocyclic aromatic group, includingmonovalent, divalent and polyvalent groups, of the aromatic andheterocyclic aromatic groups listed herein are provided in a covalentlybonded configuration in the compounds of the invention at any suitablepoint of attachment. In embodiments, aryl groups contain between 5 and30 carbon atoms. In embodiments, aryl groups contain one aromatic orheteroaromatic six-membered ring and one or more additional five- orsix-membered aromatic or heteroaromatic ring. In embodiments, arylgroups contain between five and eighteen carbon atoms in the rings. Arylgroups optionally have one or more aromatic rings or heterocyclicaromatic rings having one or more electron donating groups, electronwithdrawing groups and/or targeting ligands provided as substituents.

Arylalkyl groups are alkyl groups substituted with one or more arylgroups wherein the alkyl groups optionally carry additional substituentsand the aryl groups are optionally substituted. Specific alkylarylgroups are phenyl-substituted alkyl groups, e.g., phenylmethyl groups.Alkylaryl groups are alternatively described as aryl groups substitutedwith one or more alkyl groups wherein the alkyl groups optionally carryadditional substituents and the aryl groups are optionally substituted.Specific alkylaryl groups are alkyl-substituted phenyl groups such asmethylphenyl. Substituted arylalkyl groups include fully halogenated orsemihalogenated arylalkyl groups, such as arylalkyl groups having one ormore alkyl and/or aryl groups having one or more hydrogens replaced withone or more fluorine atoms, chlorine atoms, bromine atoms and/or iodineatoms.

As to any of the groups described herein which contain one or moresubstituents, it is understood that such groups do not contain anysubstitution or substitution patterns which are sterically impracticaland/or synthetically non-feasible. In addition, the compounds of thisinvention include all stereochemical isomers arising from thesubstitution of these compounds. Optional substitution of alkyl groupsincludes substitution with one or more alkenyl groups, aryl groups orboth, wherein the alkenyl groups or aryl groups are optionallysubstituted. Optional substitution of alkenyl groups includessubstitution with one or more alkyl groups, aryl groups, or both,wherein the alkyl groups or aryl groups are optionally substituted.Optional substitution of aryl groups includes substitution of the arylring with one or more alkyl groups, alkenyl groups, or both, wherein thealkyl groups or alkenyl groups are optionally substituted.

Optional substituents for any alkyl, alkenyl and aryl group includessubstitution with one or more of the following substituents, amongothers:

-   -   halogen, including fluorine, chlorine, bromine or iodine;    -   pseudohalides, including —CN;    -   —COOR where R is a hydrogen or an alkyl group or an aryl group        and more specifically where R is a methyl, ethyl, propyl, butyl,        or phenyl group all of which groups are optionally substituted;    -   —COR where R is a hydrogen or an alkyl group or an aryl group        and more specifically where R is a methyl, ethyl, propyl, butyl,        or phenyl group all of which groups are optionally substituted;    -   —CON(R)₂ where each R, independently of each other R, is a        hydrogen or an alkyl group or an aryl group and more        specifically where R is a methyl, ethyl, propyl, butyl, or        phenyl group all of which groups are optionally substituted; and        where R and R can form a ring which can contain one or more        double bonds and can contain one or more additional carbon        atoms;    -   —OCON(R)₂ where each R, independently of each other R, is a        hydrogen or an alkyl group or an aryl group and more        specifically where R is a methyl, ethyl, propyl, butyl, or        phenyl group all of which groups are optionally substituted; and        where R and R can form a ring which can contain one or more        double bonds and can contain one or more additional carbon        atoms;    -   —N(R)₂ where each R, independently of each other R, is a        hydrogen, or an alkyl group, or an acyl group or an aryl group        and more specifically where R is a methyl, ethyl, propyl, butyl,        phenyl or acetyl group, all of which are optionally substituted;        and where R and R can form a ring which can contain one or more        double bonds and can contain one or more additional carbon        atoms;    -   —SR, where R is hydrogen or an alkyl group or an aryl group and        more specifically where R is hydrogen, methyl, ethyl, propyl,        butyl, or a phenyl group, which are optionally substituted;    -   —SO₂R, or —SOR where R is an alkyl group or an aryl group and        more specifically where R is a methyl, ethyl, propyl, butyl, or        phenyl group, all of which are optionally substituted;    -   —OCOOR where R is an alkyl group or an aryl group;    -   —SO₂N(R)₂ where each R, independently of each other R, is a        hydrogen, or an alkyl group, or an aryl group all of which are        optionally substituted and wherein R and R can form a ring which        can contain one or more double bonds and can contain one or more        additional carbon atoms;    -   —OR where R is H, an alkyl group, an aryl group, or an acyl        group all of which are optionally substituted. In a particular        example R can be an acyl yielding    -   —OCOR″ where R″ is a hydrogen or an alkyl group or an aryl group        and more specifically where R″ is methyl, ethyl, propyl, butyl,        or phenyl groups all of which groups are optionally substituted;        and    -   —NO₂.

Specific substituted alkyl groups include haloalkyl groups, particularlytrihalomethyl groups and specifically trifluoromethyl groups. Specificsubstituted aryl groups include mono-, di-, tri, tetra- andpentahalo-substituted phenyl groups; mono-, di-, tri-, tetra-, penta-,hexa-, and hepta-halo-substituted naphthalene groups; 3- or4-halo-substituted phenyl groups, 3- or 4-alkyl-substituted phenylgroups, 3- or 4-alkoxy-substituted phenyl groups, 3- or4-RCO-substituted phenyl, 5- or 6-halo-substituted naphthalene groups.More specifically, substituted aryl groups include acetylphenyl groups,particularly 4-acetylphenyl groups; fluorophenyl groups, particularly3-fluorophenyl and 4-fluorophenyl groups; chlorophenyl groups,particularly 3-chlorophenyl and 4-chlorophenyl groups; methylphenylgroups, particularly 4-methylphenyl groups; and methoxyphenyl groups,particularly 4-methoxyphenyl groups.

As to any of the above groups which contain one or more substituents, itis understood that such groups do not contain any substitution orsubstitution patterns which are sterically impractical and/orsynthetically non-feasible. In addition, the compounds of this inventioninclude all stereochemical isomers arising from the substitution ofthese compounds.

Pharmaceutically acceptable salts comprise pharmaceutically-acceptableanions and/or cations. As used herein, the term “pharmaceuticallyacceptable salt” can refer to acid addition salts or base addition saltsof the compounds in the present disclosure. A pharmaceuticallyacceptable salt is any salt which retains at least a portion of theactivity of the parent compound and does not impart significantdeleterious or undesirable effect on a subject to whom it isadministered and in the context in which it is administered.Pharmaceutically acceptable salts include metal complexes and salts ofboth inorganic and organic acids. Pharmaceutically acceptable saltsinclude metal salts such as aluminum, calcium, iron, magnesium,manganese and complex salts. Pharmaceutically acceptable salts include,but are not limited to, acid salts such as acetic, aspartic,alkylsulfonic, arylsulfonic, axetil, benzenesulfonic, benzoic,bicarbonic, bisulfuric, bitartaric, butyric, calcium edetate, camsylic,carbonic, chlorobenzoic, −32-cilexetil, citric, edetic, edisylic,estolic, esyl, esylic, formic, fumaric, gluceptic, gluconic, glutamic,glycolic, glycolylarsanilic, hexamic, hexylresorcjnoic, hydrabamic,hydrobromic, hydrochloric, hydroiodic, hydroxynaphthoic, isethionic,lactic, lactobionic, maleic, malic, malonic, mandelic, methanesulfonic,methylnitric, methylsulfuric, mucic, muconic, napsylic, nitric, oxalic,p-nitromethanesulfonic, pamoic, pantothenic, phosphoric, monohydrogenphosphoric, dihydrogen phosphoric, phthalic, polygalactouronic,propionic, salicylic, stearic, succinic, sulfamic, sulfanlic, sulfonic,sulfuric, tannic, tartaric, teoclic, toluenesulfonic, and the like.Pharmaceutically acceptable salts may be derived from amino acids,including but not limited to cysteine. Other pharmaceutically acceptablesalts may be found, for example, in Stahl et al., Handbook ofPharmaceutical Salts: Properties, Selection, and Use, Wiley-VCH; VerlagHelvetica Chimica Acta, Zürich, 2002. (ISBN 3-906390-26-8).Pharmaceutically-acceptable cations include among others, alkali metalcations (e.g., Li⁺, Na⁺, K⁺), alkaline earth metal cations (e.g., Ca²⁺,Mg²⁺), non-toxic heavy metal cations and ammonium (NH₄ ⁺) andsubstituted ammonium (N(R′)₄ ⁺, where R′ is hydrogen, alkyl, orsubstituted alkyl, i.e., including, methyl, ethyl, or hydroxyethyl,specifically, trimethyl ammonium, triethyl ammonium, and triethanolammonium cations). Pharmaceutically-acceptable anions include amongother halides (e.g., Cl⁻, Br⁻), sulfate, acetates (e.g., acetate,trifluoroacetate), ascorbates, aspartates, benzoates, citrates, andlactate.

The compounds of this invention can contain one or more chiral centers.Accordingly, this invention is intended to include racemic mixtures,diasteromers, enantiomers, tautomers and mixtures enriched in one ormore stereoisomer. The scope of the invention as described and claimedencompasses the racemic forms of the compounds as well as the individualenantiomers and non-racemic mixtures thereof.

DETAILED DESCRIPTION OF THE INVENTION

In general, the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. The followingdefinitions are provided to clarify their specific use in the context ofthe invention.

“Supramolecular structure” refers to structures comprising an assemblyof molecules. Supramolecular structures include assemblies of molecules,such as linear block copolymers having hydrophilic, hydrophobic andfluorophilic blocks, which are selectively oriented such thathydrophilic portions of the molecules are oriented outward toward acontinuous aqueous phase, hydrophobic portions form an inner shell andfluorophilic portions of the molecules are oriented inward to form afluorous core. Supramolecular structures include assemblies ofmolecules, such as linear block copolymers having hydrophilic,hydrophobic and fluorophilic blocks, which are selectively oriented suchthat hydrophilic portions of the molecules are oriented outward toward acontinuous aqueous phase, and branched fluorophilic and hydrophobicportions are oriented inward to form a fluorophilic core and hydrophobicintermediate shell. Supramolecular structures include, but are notlimited to, micelles, vesicles, tubular micelles, cylindrical micelles,bilayers, folded sheets structures, globular aggregates, swollenmicelles, and encapsulated droplets. Supramolecular structures of thepresent invention include self-assembled structures. Supramolecularstructures may comprise the dispersed phase of a colloid, such as anemulsion or nanoemulsion.

“Semi-fluorinated” refers to chemical compounds having at least onefluorine atom, for example molecules having at least one carbon-fluorinebond.

Fluorocarbons as used herein refer to chemical compounds that contain atleast one carbon-fluorine bond.

“Perfluorinated” and “perfluorocarbon” refers to chemical compounds thatare analogs of hydrocarbons wherein all hydrogen atoms in thehydrocarbon are replaced with fluorine atoms. Perfluorinated moleculescan also contain a number of other atoms, including bromine, chlorine,and oxygen. A bromine substituted perfluorocarbon is a perfluorocarbonwherein one or more of the fluorine atoms have been replaced with abromine atom. A chlorine substituted perfluorocarbon is aperfluorocarbon wherein one or more of the fluorine atoms have beenreplaced with a chlorine atom. A chlorine and bromine substitutedperfluorocarbon is a perfluorocarbon wherein one or more of the fluorineatoms have been replaced with a chlorine atom and wherein one or more ofthe fluorine atoms have been replaced with a bromine atom.

“Perhalogenated fluorous compound” refers to fluorophilic chemicalcompounds that are analogs of a substituted or unsubstituted hydrocarbonwherein the hydrogen atoms are replaced with halogen atoms, such asfluorine, chlorine and bromine. Perhalogenated fluorous compounds canalso contain a number of other atoms, including oxygen, sulfur andnitrogen. Perhalogenated fluorous compounds include perfluorocarbons andsubstituted perfluorocarbons, such as chlorine substitutedperfluorocarbons, bromine substituted perfluorocarbons and chlorine andbromine substituted perfluorocarbons.

“Emulsion” refers to a mixture of two or more immiscible substances,such as a mixture of two immiscible liquids. Emulsions are a type ofcolloid that comprise at least one dispersed phase dispersed in acontinuous phase. Emulsions are broadly defined as two immiscible phasesin which a first phase is dispersed within a second phase, such as atwo-phase system in which one liquid is dispersed throughout a secondliquid in the form of small droplets. This energy can either be suppliedby mechanical equipment or the chemical potential inherent within thecomponents. The two phases of an emulsion are generally referred to asthe continuous phase and the dispersed phase, with the dispersed phasetypically present as a smaller volume percentage. A dispersion of oil inwater is referred to as an oil-in-water (o/w) emulsion. For o/wemulsions the emulsifying agent is typically more soluble in the aqueousphase. The reverse emulsion, water-in-oil, is abbreviated w/o and isstabilized by surfactants that are more stable in the oil phase. In anaqueous emulsion, the continuous phase is an aqueous solution.

Emulsions are not thermodynamically stable, but the stability can beimproved by additives such as surfactants. As non-equilibrium systems,the formation of nanoemulsions generally requires an input of energy.High-energy emulsification methods commonly involve the introduction ofmechanical shear through such equipment as high-shear stirrers,high-pressure homogenizers, microfluidizers or ultrasound generators. Amicrofluidizer is the piece of equipment used in the pharmaceuticalindustry for the production of emulsions that works by dividing a streamof liquid into two parts, passing each through a narrow opening and thencolliding the streams under high pressure. The high shear forces createdby the collision provide very fine emulsions with generally narrowparticle size distributions. In typical usage, a coarse emulsion(diameter >1 μm) is first formed by some other method, and the size ofthat larger emulsion is reduced in the microfluidizer. The final dropletsize and distribution shape will be dependent upon both the emulsioncomponents (surfactant amount, oil volume percent, etc.) and theprocessing parameters (time, temperature, pressure etc.). As the desireddroplet size decreases, the energy required for formation increases.Ultrasonic emulsification is also effective to reduce the size ofemulsion droplets into the nanoscale. Emulsions can also be formed bychanging the temperature of a mixture of immiscible liquids, for exampleby rapid cooling or heating to produce kinetically stable emulsions withsmall droplet sizes and narrow size distributions.

Emulsions include nanoemulsions comprising nanoscale droplets of oneimmiscible liquid dispersed within another. As used herein ananoemulsion is a heterogeneous system composed of one immiscible liquiddispersed as droplets within another liquid, where the average dropletdiameter is below 1000 nm.

“Flocculation” refers to a process in which clusters of two or moredroplets behave kinetically as a unit, but individual droplets stillmaintain their identity. Flocculation may be reversible, or lead tocoalescence, which is irreversible.

“Coalescence” is the collision, and subsequent irreversible fusion, oftwo droplets. The ultimate end of coalescence is complete phaseseparation. Flocculation precedes coalescence, so the same methods thatare appropriate for prevention of flocculation also prevent coalescence.A thick, surfactant film adsorbed at the interface is often sufficientto prevent coalescence, whether in nano- or macro-emulsions.

“Ostwald ripening” refers to the growth in the size of emulsion dropletsas the contents of one drop diffuse into another. The driving force forthis growth is the difference in chemical potential between droplets,which is generally not substantial for droplets larger than 1 μm.Therefore, Ostwald ripening primarily affects nanoemulsions, and is animportant factor for nanoemulsions for therapeutic applications.

“Polymer” refers to a molecule comprising a plurality of repeatingchemical groups, typically referred to as monomers. A “copolymer”, alsocommonly referred to as a heteropolymer, is a polymer formed when two ormore different types of monomers are linked in the same polymer. “Blockcopolymers” are a type of copolymer comprising blocks or spatiallysegregated domains, wherein different domains comprise differentpolymerized monomers. In a block copolymer, adjacent blocks areconstitutionally different, i.e. adjacent blocks comprise constitutionalunits derived from different species of monomer or from the same speciesof monomer but with a different composition or sequence distribution ofconstitutional units. Different blocks (or domains) of a block copolymermay reside on different ends of a polymer (e.g. [A][B]), or may beprovided in a selected sequence ([A][B][A][B]). “Diblock copolymer”refers to block copolymers having two different chemical blocks.“Triblock copolymer” refers to block copolymers having three differentchemical blocks. Polymers of the present invention include blockcopolymers having a first block comprising a smaller polymer (e.g., 2 to30 monomers), such as a fluorocarbon, including but not limited to, afluorocarbon such as a fluorinated or perfluorinated alkane, a secondinterior hydrophobic block, and a third block comprising a largerpolymer (e.g., 10-300) such as a PEG polymer having 10 to 270 monomers.Block copolymers of the present invention are capable of undergoingself-assembly to make supramolecular structures, such as encapsulateddroplets. As used herein, the term block copolymer includes compositionscomprising a first block comprising a PEG polymer conjugated to a secondblock comprising a hydrophobic polymer and further conjugated to a thirdblock comprising a perfluorinated or semifluorinated molecular domain,such as a perfluorinated or semifluorinated alkane or a perfluorinatedor semifluorinated tail. As used herein, the term block copolymer alsoincludes functionalized block copolymers, such as copolymers havingadditional moieties for targeting a supramolecular structure to anactive site, for stabilizing a supramolecular structure or for selectingthe release kinetics of a supramolecular structure containing afluorinated therapeutic compound.

As used herein “hydrophilic” refers to molecules and/or components(e.g., functional groups, blocks of block polymers, etc.) of moleculeshaving at least one hydrophilic group, and hydrophobic refers tomolecules and/or components (e.g., functional groups of polymers, andblocks of block copolymers etc.) of molecules having at least onehydrophobic group. Hydrophilic molecules or components thereof tend tohave ionic and/or polar groups, and hydrophobic molecules or componentsthereof tend to have nonionic and/or nonpolar groups. Hydrophilicmolecules or components thereof tend to participate in stabilizinginteractions with an aqueous solution, including hydrogen bonding anddipole-dipole interactions. Hydrophobic molecules or components tend notto participate in stabilizing interactions with an aqueous solution and,thus often cluster together in an aqueous solution to achieve a morestable thermodynamic state. In the context of block copolymers of thepresent invention, a hydrophilic block is more hydrophilic than ahydrophobic group of an amphiphilic block copolymer, and a hydrophobicgroup is more hydrophobic than a hydrophilic block of an amphiphilicpolymer.

As used herein “fluorophilic” refers to molecules and/or components(e.g., functional groups, blocks of block polymers etc.) of moleculeshaving at least one fluorophilic group. A fluorophilic group is one thatis capable of participating in stabilizing interactions with a fluorousphase. Fluorophilic groups useful in block copolymers compounds of theinvention include, but are not limited to, fluorocarbon groups,perfluorinated groups and semifluorinated groups.

In the context of the present invention the term patient is intended toinclude a subject such as an animal. Patient includes a mammal, forexample human subject. Patient includes a subject undergoing a medicalprocedure, such as undergoing the administration of anesthesia or othermedical procedure.

Before the present methods are described, it is understood that thisinvention is not limited to the particular methodology, protocols, celllines, and reagents described, as these may vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to limit thescope of the present invention which will be limited only by theappended claims.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural reference unless thecontext clearly dictates otherwise. Thus, for example, reference to “acell” includes a plurality of such cells and equivalents thereof knownto those skilled in the art, and so forth. As well, the terms “a” (or“an”), “one or more” and “at least one” can be used interchangeablyherein. It is also to be noted that the terms “comprising”, “including”,and “having” can be used interchangeably.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. All publications mentioned herein areincorporated herein by reference for the purpose of describing anddisclosing the chemicals, cell lines, vectors, animals, instruments,statistical analysis and methodologies which are reported in thepublications which might be used in connection with the invention.Nothing herein is to be construed as an admission that the invention isnot entitled to antedate such disclosure by virtue of prior invention.

FIG. 1 provides a schematic illustration of the formation asupramolecular structure in an emulsion comprising a hydrophobic drugand semi-fluorinated block copolymers comprising a hydrophilic block, ahydrophobic block and a fluorophilic block. Without being bound by anytheory, FIG. 1 is provided to illustrate aspects of the inventionrelating to one potential structure of the dispersed phase droplets inemulsions and formulations of the invention, and is not intended tolimit the structure of the dispersed phase droplets. As will beunderstood by one of skill in the art FIG. 1 is merely a schematicrepresentation to convey an understanding of the components of thepresent emulsions, and is not intended to provide the actual structures,physical dimensions and relative arrangement of the components of thedispersed droplet phase.

In embodiments, the illustrated configurations are stabilized byself-assembly of the hydrophilic blocks of the semi-fluorinated blockcopolymers in a configuration so as to associatively interact with theaqueous solution, while simultaneously positioning the fluorophilic andhydrophobic blocks in a configuration toward the interior of thedroplet. In some embodiments, for example, the fluorophilic blocks ofthe semifluorinated block copolymers align to form a fluorous core. Insome embodiments, for example, the hydrophobic drug is noncovalentlyassociated with the intermediate shell region of the hydrophobichydrophobic block of the semi-fluorinated block copolymers. Inclusion ofa perhalogenated fluorous compound additive further stabilizes thedroplets and provides more stable emulsions. Such a configurationadvantageously provides a technique for dispersal of the hydrophobicdrug in the aqueous solution, such that the hydrophobic drug can beadministered intravenously to a patient in an aqueous solution basedemulsion.

In embodiments, the supramolecular structure is initially formed with anexternal facing hydrophilic shell. In embodiments, the supramolecularstructure is initially formed with an intermediate hydrophobic shell. Inembodiments, the supramolecular structure is initially formed with afluorophilic core. In embodiments, the supramolecular structure isformed with a combination of an external facing hydrophilic shell, anintermediate hydrophobic shell a fluorophilic core. In some embodiments,the hydrophobic drug begins accumulating in the supramolecular structureat the intermediate hydrophobic shell. In some embodiments, theperhalogenated fluorous compound begins accumulating in thesupramolecular structure at the fluorophilic core. Optionally, theperhalogenated fluorous compound accumulates at the fluorophilic corewhile the hydrophobic drug accumulates an intermediate hydrophobicshell, as shown in the embodiment illustrated in FIG. 1. In this way,the semi-fluorinated block copolymers provide an interface between thedroplets comprising the hydrophobic drug and the aqueous solution.

In embodiments, the perhalogenated fluorous compound additive functionsto stabilize the emulsion. Optionally, the perhalogenated fluorouscompound additive functions as a surfactant. Optionally, theperhalogenated fluorous compound additive functions as a component ofthe dispersed phase, such as at a fluorophilic core of a micelle-likesupramolecular structure. Optionally, the perhalogenated fluorouscompound additive functions to stabilize the dispersed phase.

The invention may be further understood by the following non-limitingexamples.

EXAMPLE 1 Emulsion-Based Formulations of Propofol

This example provides a description of compositions and physicalproperties of specific examples of emulsions useful in the presentformulations and therapeutic methods. In addition, the results of animalmodels experiments are provided demonstrating clinical efficacy forexamples of the present formulations and therapeutic methods. Thedescription and experimental results are divided into two analysissections (Analysis Section No. 1 and Analysis Section No. 2) which takentogether demonstrate useful properties and applications of certainembodiments of the present invention.

Analysis Section No. 1

Commercial propofol (Diprivan) consists of an Intralipid® emulsion ofthe active principle 2,6-diisopropylphenol. This emulsion is usedextensively in anesthesiology practice to induce and maintain generalanesthesia. Propofol is also used for procedural sedation (e.g.colonoscopy) and for sedation in intensive care units.

The current formulation of propofol is subject to a variety of problems,one of the most important being the ability to support bacterial andfungal growth. This is due to the main ingredient of Intralipid®:soybean oil or a similar lipid. Because of the risk of contamination,tubing and open vials of propofol must be replaced every twelve hours.In addition, infusion at a high rate or as a large bolus can lead tolipid intolerance, and may contribute to ‘propofol infusion syndrome, arare but serious complication that limits its use in the intensive careunit. The development of a non-lipidic propofol emulsion would addressthese problems and thus would be an important advance.

The present example demonstrates the ability of semifluorinatedsurfactants to stabilize emulsions of various chemicals. For example, wehave identified several triblock copolymers that are able to form astable propofol emulsion without the addition of any lipid component. Incertain embodiments, the only additive used is a small percentage of aperhalogenated fluorous compound. Emulsions have been studied in ratsand shown to be as effective as commercial propofol emulsions ininducing loss of consciousness. The polymers evaluated comprise a PEGmoiety to ensure water solubility, a hydrophobic block, typically adecyl group to complex the propofol, and a medium-sized fluorous groupfor enhancing the emulsion stability. Different polymer architectureshave been tested and all of them are remarkably effective, although withsome differences. For instance, addition of a perhalogenated fluorouscompound to a formulation containing a linear triblock copolymer isuseful for generating stable emulsions with propofol.

The emulsions described in this example are much simpler in compositionthan the current commercial propofol and offer the advantage that theydo not support microbial growth. In the new emulsions, simple saline canbe used to ensure isotonicity instead of glycerol, a chemical requiredfor Intralipid® stability. Importantly, the new emulsions are aseffective as the currently used propofol.

Emulsion with Linear Semifluorinated Triblock Copolymer andPerhalogenated Fluorous Compound

The physical properties of propofol emulsions comprising the linearsemifluorinated triblock copolymer (M1H10F8) and perfluorooctylbromide(PFOB) were characterized.

Specifically, the following formulations were evaluated.

-   Formulation 1: 15.97 mL saline, 280 mg M1H10F8, 0.18 mL propofol,    0.850 mL PFOB-   Formulation 2: 15.12 mL saline, 280 mg M1H10F8, 0.18 mL propofol,    1.7 mL PFOB-   Formulation 3: 13.42 mL saline, 280 mg M1H10F8, 0.18 mL propofol,    3.4 mL PFOB

FIG. 2 provides a plot showing the mean droplet diameter (nm) for theemulsions corresponding to Formulations 1, 2 and 3 evaluated as afunction of time (days). In FIG. 2, Formulation 1 corresponds to 5%PFOB, Formulation 2 corresponds to 10% PFOB and Formulation 3corresponds to 20% PFOB. As shown in FIG. 2, formulations 1-3 formedstable emulsions with mean droplet diameters of between about 210 and250 nm. Over a period of about 28 days, the mean droplet diameter ofFormulation 1 increased to about 375 nm, while the mean dropletdiameters of Formulations 2 and 3 increased to about 300 nm. The resultsdemonstrate the present emulsions are compatible with formulation usingsaline solution, which has particular relevance for clinic use.

Animal Studies

FIGS. 3 and 4 show the results of animal studies for the administrationof propofol emulsions. All animal studies were approved by theUniversity of Wisconsin Animal Care and Use Committee, Madison, Wis.,and were performed in accordance with the guidelines laid out in theGuide for the Care and Use of Laboratory Animals published by theNational Research Council.

Experiments to measure loss and recovery of the righting reflex werecarried out in six male Spraque-Dawley rats (Harlan Spraque-Dawley,Inc., Indianapolis, Ind.) weighing approximately 280 g. The rats werereceived from the supplier with a surgically implanted jugular catheter.Different propofol formulations were tested: 1) lipid-based propofolformulation as in current clinical use (Propofol: Diamonds); 2)Formulation 5 (B8: Squares: 16.82 mL saline, 420.5 mg (25 mg/ml)M1μH10F8, 0.18 mL propofol); 3) Formulation 4 (L3: Triangles; 16.82 mLsaline, 420.5 mg M1H10-O-F3 (25 mg/mL)), 201.8 g E80 (12 mg/mL), 0.18 mLpropofol) and 4) Formulation 3 (F8: Xs; 13.42 mL saline, 280 mg M1H10F8,0.18 mL propofol, 3.4 mL PFOB). For each formulation, five differentdoses were administered three times each.

The propofol emulsions were administered by first restraining the ratwith a towel. The plug placed at the end of the catheter was thenremoved and replaced with a 23-gauge needle connected to an insulin-typesyringe. To remove the heparin-based fill solution and check that noblockage was obstructing the catheter, the syringe plunger was slowlywithdrawn until blood filled the catheter. The 23-gauge needle was thenconnected to the syringe containing the propofol emulsion to be tested.The rat was then placed in a transparent cage for observation. Forty μLof the emulsion, corresponding to the volume of the catheter, wasinjected to prime the catheter and then the administration of theemulsion was started. The emulsion injection rate was controlled throughan infusion pump (11 plus; Harvard Apparatus, Holliston, Mass.). A bolusdose was delivered within 20 s regardless of the volume. Loss ofrighting reflex (LORR) was evaluated by rolling the rat onto its backand observing whether the animal was able to right itself. The times toachieve and to recover from LORR were recorded. When the rat completelyrecovered from LORR, the catheter was flushed with 0.04 ml of a normalsaline solution to remove the residual emulsion and then refilled with0.04 ml of a heparin-based fill solution. The end of the catheter wassealed with a sterile plug.

FIG. 3 provides plots of time to LORR (s) as a function of dose (mg/kg).FIG. 4 provides plots of time to Time to Return of Righting Reflex (s)as a function of dose (mg/kg). Data are plotted as time to loss orrecovery of righting reflex as a function of drug dose, expressed on amg/kg basis for the propofol component of the nanoemulsion. The x-axisintersection is the calculated ED50 for inducing LORR as a surrogate forunconsciousness. All three formulations proved effective with similarED50 values. The data shown in FIGS. 3 and 4 indicate efficacies of thepresent emulsions having semifluorinated block copolymer are comparableto the lipid-based propofol formulation currently in use.

Experimental Section

Structures of linear, branched, and miktoarm amphiphiles with associatednomenclature are shown below.

Mx refers to the mPEG hydrophilic block with x being the averagemolecular weight in thousands. For non-linear amphiphiles, μ specifiesmiktoarm architecture, respectively. H# corresponds to the number ofhydrogenated carbon atoms and F# corresponds to the number offluorinated carbon atoms. For the linear polymers, the presence orabsence of —O— indicates the presence or absence of an ether linkagebetween the blocks.

Materials

All fluorinated compounds were obtained from SynQuest Laboratories, Inc.(Alachua, Fla., USA), Lipoid E80 was purchased from Lipoid GmbH(Ludwigshafen, Germany). All solvents were of ACS grade or higher andwere purchased from Sigma-Aldrich (St. Louis, Mo., USA). All otherreagents were purchased from Sigma Aldrich (St. Louis, Mo., USA) andwere used as received, unless otherwise specified. Chromatographicseparations were performed using Silicycle 60 Å SiO₂. Surfactants werepurified automated flash chromatography using a Combi Flash® Rf 4xsystem (Teledyne Isco, Lincoln, Nebr., USA) equipped with a Gold C-18aqueous reverse phase cartridge. ¹H- and ¹⁹F-NMR spectra were obtainedon Varian Unity-Inova 400 and Unity-Inova 500 spectrometers usingdeuterochloroform (CDCl₃) as the solvent with TMS as an internalreference.

Methods

mPEG mesylate (Mx-OMs). To a dry 100 mL roundbottom flask charged withargon were added 50 mL DCM and 5 g monomethyl poly(ethylene glycol)alcohol 5 g M1-OH. The mixture was cooled to 0° C. before adding 2 mLTEA, which was allowed to stir for 30 minutes before 1 mLmethanesulfonyl chloride was added. The reaction was allowed to stirovernight as it warmed to room temperature. The reaction was thendiluted with 100 mL DCM and washed with 3×50 mL aliquots saturatedammonium chloride solution, dried over magnesium sulfate and thenreduced to a minimum volume under reduced pressure. The mPEG-OMs wasthen precipitated with cold ether, vacuum filtered, and freeze driedfrom 50/50 DCM/benzene to give a white, crystalline produce in 67% yieldmPEG₁₀₀₀-OMs. mPEG₁₀₀₀-OMs MALDI: Distribution centered on [M+Na⁺]=1063,PDI of starting mPEG 1.27. NMR: ¹H NMR (400 MHz, CDCl₃): δ 4.38 (m, 2H),3.82 (m, 1H), 3.77 (m, 2H), 3.64 (m, 89H), 3.55 (m, 2H), 3.47 (m, 1H),3.38 (s, 3H), 3.09 (s, 3H).

Linear alcohols. HO-H10F8 (2): To a dry 10 mL roundbottom flask wereadded 1.02 mL (5.75 mmol) 9-decen-1-ol and 1.34 mL (5.0 mmol)perfluorooctyl iodide. The mixture was degassed at room temperature withargon for 45 minutes before 8.2 mg (0.05 mmol) AIBN were added and themixture slowly heated to 80° C. while being very rapidly stirred with asmall stir bar. This reaction was allowed to run overnight. The reactionwas then cooled to room temperature, diluted with 100 mL DCM, washedwith 1×50 mL aliquot each Na₂S₂O₃ and brine. The organic layers weredried over MgSO₄ and condensed under reduced pressure to give anoff-white solid (1). This was then dissolved in 10 mL acetic acid andstirred with 0.98 g zinc powder for 24 hours open to the air. Thereaction was then quenched with 200 mL saturated NaHCO₃ solution andextracted with 300 mL DCM. The organic layers were then washed with1×100 mL aliquot each saturated NaHCO₃ solution and brine and then driedover MgSO₄ and concentrated under reduced pressures to give a whitesolid. The solid was recrystallized twice from hot toluene to give pure(2) HO-H10F8 in 48% yield. NMR: ¹H NMR (400 MHz, CDCl₃): δ 3.65 (t,J=6.9 Hz, 2H), 2.05 (ttt, J=18, 9.5, 2 Hz, 2H), 1.65-1.52 (m, 4H),1.4-1.23 (m, 12H). ¹⁹F NMR (376 MHz, CDCl₃): δ −81.15 (3F), −114.77(2F), −122.32 (6F), −123.11 (2F), −123.92 (2F), −126.49 (2F).

HO-H10-O-F3 (3): To a dry roundbottom, on ice under argon, were added 25mL dry DCM, 9-decen-1-ol (2.5 mL, 13 mmol) and TEA (4.3 mL, 31 mmol).This was allowed to react for 30 minutes before methanesulfonyl chloride(1.3 mL, 16 mmol) was added dropwise. After running overnight, thereaction was diluted with 50 mL DCM and then washed with 3×50 mL ofsaturated ammonium chloride solution. The organic layer was then driedover magnesium sulfate and concentrated under reduced pressure to give3.21 g (quantitative yields) of yellow oil. NMR: ¹H NMR (400 MHz,CDCl₃): δ 5.81 (ddt, J=16.5, 10, 6.5 Hz, 1H), 4.99 (ddt, J=16.5, 2, 1Hz, 1H), 4.93 (ddt, J=10, 2, 1 Hz, 1H), 4.22 (t, J=7 Hz, 2H), 3.00 (s,3H), 2.04 (qt, J=6.5, 1 Hz, 2H), 1.60 (q, J=7 Hz, 2H), 1.41-1.29 (m,10H).

To a 100 mL oven-dried roundbottom, under argon, were added 35 mL of THFand 761 mg of NaH. The suspension was cooled to 0° C. over the course of10 minutes before 28 mmol of semi-fluorinated alcohol were added 3.25 mL1H,1H-perfluorobutan-1-ol (F3H1-OH) was added dropwise over the courseof 1 hour. Then 3.20 g (13 mmol) of 9-decen-1-yl methane sulfonate wereadded (as a solution in 10 mL of anhydrous THF). This was then warmedslowly to reflux and allowed to react for 24 hours. The reaction wasthen allowed to cool and diluted with 100 mL of DCM. This was washedwith 3×50 mL aliquots of saturated ammonium chloride solution and thendried over magnesium sulfate and concentrated under reduced pressure togive an opaque, yellow liquid. The product was then purified by columnchromatograph (4% ethyl acetate in hexanes) to give 3.83 g (86% yield)and of product as a clear liquid. 10-(1H,1H-perfluorobutoxy)dec-1-eneNMR: ¹H NMR (400 MHz, CDCl₃): δ 5.81 (ddt, J=16.5, 10, 6.5 Hz, 1H), 4.99(ddt, J=16.5, 2, 1Hz, 1H), 4.93 (ddt, J=10, 2, 1Hz, 1H), 3.90 (tt, J=14,2 Hz, 2H), 3.58 (t, J=7 Hz, 2H), 2.04 (qt, J=6.5, 1 Hz, 2H), 1.60 (q,J=7 Hz, 2H), 1.41-1.29 (m, 10H). ¹⁹F NMR (376 MHz, CDCl₃): δ −81.51(3F), −121.09 (2F), −128.28 (2F).

To an oven-dried round-bottom flask was added BH₃-THF (1.0M, 16.5 mmol).The solution was diluted with 10 mL of dry THF and then cooled to 0° C.

The semi-fluorinated alkene ether 3.83 g10-(1H,1H-perfluorobutoxy)dec-1-ene was added dropwise and the reactionwas allowed to stir at room temperature for 16 h. The reaction wascooled to 10° C. followed by addition of NaOH solution (3M, 20 mL).Hydrogen peroxide (30 wt. % in water, 6 mL) was added at 10° C. Thereaction mixture was stirred at 50° C. for 2 h and then cooled to roomtemperature. Ether (20 mL) was added and the organic phase was washedwith H₂O (20 mL), brine (20 mL), dried over magnesium sulfate andconcentrated under reduced pressure to give 3.9 g (98% yield)HO-H10-O-F3 (3) of clear oil. HO-H10-O-F3 NMR: ¹H NMR (400 MHz, CDCl₃):δ 3.90 (tt, J=14, 2 Hz, 2H), 3.64 (t, J=7 Hz, 2H), 3.58 (t, J=7 Hz, 2H),1.60 (septet, J=7 Hz, 4H), 1.41-1.29 (m, 12H). ¹⁹F NMR (376 MHz, CDCl₃):δ −81.51 (3F), −121.08 (2F), −128.28 (2F).

Miktoarm alcohols. HO-μF8H10 (9): 5 g decanol was dissolved in anhydrousDCM (50.0 mL) and flask flushed with Ar. 8.80 mL TEA was added tosolution and flask cooled in ice bath and 3.70 mL MsCI was then addedvia syringe, dropwise, and reaction stirred under Ar overnight, allowingthe ice bath to warm to room temperature. The reaction was then stoppedand washed with 4×100 mL aliquots of aqueous NH₄Cl, dried over MgSO₄ andsolvent removed under vacuum. Yield: 7.413 g decyl methane sulfonate(99%). Decyl methane sulfonate:¹H NMR (400 MHz, CDCl₃): δ 4.22 (t, J=6.6Hz, 2H), 3.00 (s, 3H), 1.75 (p, J=6.7 Hz, 2H), 1.42 (t, J=7.5 Hz, 2H),1.26 (m, 12H), 0.88 (t, J=6.8 Hz, 3H).

2-phenyl-1,3-dioxan-5-ol (4): glycerol (24.31 g, 264.0 mmol) andbenzaldehyde (28.03 g, 264.1 mmol) were dissolved in anhydrous toluene(70 mL) and flask flushed with argon. P-toluenesulfonic acid monohydrate(115.1 mg, 0.61 mmol) was added and flask fitted with Dean-Stark trapand heated to reflux. After 72 hours, the reaction was cooled to roomtemperature and washed with sodium bicarbonate (100 mL), brine (100 mL),dried over MgSO₄, and remaining toluene was placed in freezer overnightto crystallize out product. White crystals were then collected byfiltration and dried under vacuum to yield 4.487 g (24.90 mmol, 9%).NMR: ¹H NMR (400 MHz, CDCl₃): δ 7.48 (m, 2H), 7.36 (m, 3H), 5.50 (s,1H), 4.12 (dd, J=12.0, 1.4 Hz, 2H), 4.02 (dd, J=12.0, 1.3 Hz, 2H), 3.54(dt, J=10.6, 1.5 Hz, 1H), 3.36 (d, J=10.5 Hz, 1H).

5-(decyloxy)-2-phenyl-1,3-dioxane (5): 3.686 g 2-phenyl-1,3-dioxan-5-ol(4) was dissolved in 80 mL anhydrous toluene and 2.30 g crushed added.Reaction fitted with Dean-Stark trap and heated to reflux for 6 hours.The reaction was then cooled, and 7.413 decyl methane added as solutionin toluene (20 mL). The reaction was fitted with a condenser and heatedto reflux for 5 days. The reaction was then cooled to room temperature,diluted with 100 mL water, extracted with 3×100 mL aliquots of ether,dried over MgSO₄ and solvents removed under reduced pressure. Crude oilpurified by flash column (5% ethyl acetate in hexanes) to obtain 3.309 g5-(decyloxy)-2-phenyl-1,3-dioxane (10.33 mmol, 51%) (5). ¹H NMR (400MHz, CDCl₃): δ 7.50 (m, 2H), 7.33 (m, 3H), 5.54 (s, 1H), 4.31 (dd,J=12.4, 1.2 Hz, 2H), 4.02 (dd, J=12.4, 1.6 Hz, 2H), 3.53 (t, J=6.8 Hz,2H), 3.24 (t, J=2.0 Hz, 1H), 1.65 (p, J=6.8 Hz, 2H), 1.28 (m, 14H), 0.88(t, J=6.8 Hz, 3H).

3-(benzyloxy)-2-(decyloxy)propan-1-ol (6): 7.745 g 5 was dissolved in 50mL anhydrous DCM and flask flushed with Ar. The reaction was cooled inan ice bath, and 48.3 mL 1 M DIBAL was added dropwise over 20 minutesand the reaction stirred overnight, allowing the reaction to warm toroom temperature. The reaction was quenched dropwise with 30 mL 0.5 M,then diluted with 10 mL 0.5 M NaOH and extracted with 2×50 mL aliquotsDCM. Combined organics were washed with 2, 100 mL aliquots Rochelle'ssalt, 100 mL brine, dried over MgSO₄ and solvent removed under reducedpressure. Crude oil was purified with silica column (0-5% methanol inDCM) to yield 6.01 g 3-(benzyloxy)-2-(decyloxy)propan-1-ol (6) (77%). ¹HNMR (400 MHz, CDCl₃): δ 7.36-7.26 (m, 5H), 4.54 (AB quartet, 2H), 3.74(m, 1H), 3.66-3.48 (m, 6H), 2.10 (dd, J=5.7, 6.9 Hz, 1H), 1.57 (p, J=7.0Hz, 2H), 1.26 (m, 14H), 0.88 (t, J=6.8 Hz, 3H).

3-(benzyloxy)-2-(decyloxy)propyl methanesulfonate (7): 6.01 g of 6 wasdissolved in 300 mL anhydrous DCM and flask flushed with Ar. 5.20 mL TEAwas added and reaction cooled in ice bath. 2.20 mL MsCI was addeddropwise and the reaction was stirred under Ar overnight, allowing icebath to warm to room temperature. The reaction was then diluted with DCM(50 mL) and washed with 3 aliquots saturated NH₄CI solution, dried overMgSO₄ and solvents removed under reduced pressure to give a pale yellowoil. 7 7.102 g (95% yield). 7 ¹H NMR (400 MHz, CDCl₃): δ 7.33 (m, 5H),4.54 (dd, J=12.1, 2.3 Hz, 2H), 4.39 (dd, J=10.9, 3.8 Hz, 1H), 4.27 (dd,J=10.8, 5.7 Hz, 1H), 3.70 (p, J=4.7 Hz, 1H), 3.55 (m, 4H), 3.00 (s, 3H),1.56 (p, J=6.8 Hz, 2H), 1.28 (m, 14H), 0.88 (t, J=6.8 Hz, 3H).

((2-(decyloxy)-3-(1H,1Hperfluorononyloxy)propoxy)methyl)benzene (8):3.160 g 7 was dissolved in anhydrous BTF, and 5.12 g F8H1-OH added, andflask flushed with Ar. 667 mg NaH were slowly added, and reaction heatedto reflux for 3 days. Reaction was quenched dropwise with H₂O andfurther diluted with water and DCM and layers separated. Organics driedover MgSO₄ and solvents evaporated under vacuum. Purified by columnchromatography (5% ethyl acetate in hexanes) to obtain pure 8 in 67%yield (3.985 g). 8a ¹H NMR (400 MHz, CDCl₃): δ 7.33 (m, 5H), 4.54 (s,2H), 4.00 (t, J=13.9 Hz, 2H), 3.76 (dd, J=10.4, 4.0 Hz, 1H), 3.68 (dd,J=10.4, 5.6 Hz, 1H), 3.61 (p, J=4.7 Hz, 1H), 3.54 (m, 4H), 1.56 (p,J=6.8 Hz, 2H), 1.28 (m, 14H), 0.88 (t, J=6.8 Hz, 3H). ¹⁹F NMR (376 MHz,CDCl₃): δ −81.19 (3F), −120.22 (m, 2F), −122.38 (m, 6F), −123.12 (m,2F), −123.80 (m, 2F), −126.52 (m, 2F).

HO-μH10F8 (9): 3.679 g 8 was dissolved in 180 mL anhydrous DCM and 2.10mL anisole was added. Flask was flushed with Ar and cooled in ice bath.1.951 g AlCl₃ was added and reaction was stirred under Ar. After 18hours reaction was quenched dropwise with 0.5 M HCl, and further dilutedwith 0.5 M HCl and layers separated. Organic layer was washed with H₂O,brine, dried over MgSO₄ and solvents were removed under reducedpressure. Crude oil was purified by column chromatography, 10-40% ethylacetate in hexanes to give pure 2.875 g pure 9 (89% yield). HO-μH10F8 ¹HNMR (400 MHz, CDCl₃): δ 4.00 (t, J=13.7 Hz, 2H), 3.73 (m, 3H), 3.57 (m,4H), 2.00 (t, J=6.1 Hz, 1H), 1.57 (p, J=7.1 Hz, 2H), 1.26 (m, 14H), 0.88(t, J=6.8 Hz, 3H). ¹⁹F NMR (376 MHz, CDCl₃): δ −81.25 (t, J=9.9 Hz, 3F),−120.16 (m, 2F), −122.42 (m, 6F), −123.16 (m, 2F), −123.82 (m, 2F),−126.57 (m, 2F).

Linear and Branched amphiphiles. General procedure: To a dry 100 mLflask charged with argon were added 50 mL α,α,α-trifluorotoluene (BTF)and 4.0 mmol alcohol. The mixture was cooled on ice and 5.0 mmol NaHwere added. This was allowed to stir for 30 minutes before adding 2.0mmol mPEG-OMs. The reaction was then heated to reflux and allowed toreact for a 7 days. The reaction was cooled, diluted with 100 mL DCM andwashed with 150 mL NH₄Cl solution, 50 mL brine and dried over MgSO₄. Theorganics were then concentrated to a minimum volume and the surfactantsprecipitated upon addition of 500 mL cold ether. The solid was collectedby vacuum filtration and then purified by reverse-phase chromatography.The product was then freeze dried from 50/50 DCM/Benzene to give apowdery solid.

M1 H10-O-F3: 52% Yield, MALDI: Distribution centered on [M+Na⁺]=1406, ¹HNMR (400 MHz, CDCl₃): δ 3.90 (tt, J=13.7, 1.7 Hz, 2H), 3.84-3.81 (m,1H), 3.75-3.71 (m, 1H), 3.68-3.61 (m, 95H), 3.60-3.54 (m, 6H), 3.44 (t,J=6.9 Hz, 2H), 3.38 (s, 3H), 1.58 (sextet, J=7.1 Hz, 4H), 1.35-1.22 (m12H). ¹⁹F NMR (376 MHz, CDCl₃): δ −81.39 (3F), −121.12 (2F), −128.20(2F); M1H10F8: 79% Yield, MALDI: Distribution centered on [M+Na⁺]=1671,¹H NMR (400 MHz, CDCl₃): δ 3.86-3.80 (m, 1H), 3.76-3.54 (m, 98H), 3.45(t, J=6.7 Hz, 2H), 3.38 (s, 3H), 2.05 (ttt, J=19, 8.2, 2 Hz, 2H), 1.57(septet, J=6.7 Hz, 2H), 1.42-1.20 (m, 10H). ¹⁹F NMR (376 MHz, CDCl₃): δ−81.19 (3F), −114.74 (2F), −122.36 (6F), −123.16 (2F), −123.96 (2F),−126.57 (2F); All amphiphiles are at most as polydisperse as the mPEG-OHthey are synthesized from (vide supra).

Miktoarm amphiphiles. Typical procedure: Alcohol and mPEG-OMs weredissolved in 20-75 mL BTF to achieve 20 mM concentrations. Flask flushedwith Ar, NaH added (to achieve 40 mM concentration), and flask heated toreflux. After 5 days reaction was cooled to room temperature andquenched dropwise with H₂O. The organics were dried over MgSO₄. Solventsevaporated under reduced pressure, and crude polymer purified by reversephase chromatography. Solid was lyophilized to give white, fluffyproduct.

M1μH10F8: 89% Yield, MALDI: Distribution centered on [M+Na⁺]=1715, ¹HNMR (400 MHz, CDCl₃): δ 4.02 (t, J=14 Hz, 2H), 3.81 (m, 1H), 3.75 (dd,J=10.4, 3.6 Hz, 2H), 3.67-3.62 (m, 80H), 3.59-3.51 (m, 7H), 3.46 (m,1H), 3.38 (s, 3H), 1.57 (p, J=7.2 Hz, 2H), 1.26 (m, 16H), 0.88 (t, J=6.8Hz, 3H). ¹⁹F NMR (400 MHz, CDCl₃): δ −81.14 (3F), −120.18 (2F), −122.36(6F), −123.09 (2F), −123.77 (2F), −126.48 (2F). All amphiphiles are atmost as polydisperse as the mPEG-OH they are synthesized from (videsupra).

Emulsion Preparation

Surfactant with or without E80 additive emulsion. To a 50 mL falcon tubewere added 16.82 mL normal saline, 25 mg mL⁻¹ surfactant and, ifincluded, 12 mg mL⁻¹ Lipoid E80. This was vortexed for 1 minute andsonicated for 30 minutes with heating. The resulting solution wasallowed to cool to room temperature and then 0.18 mL propofol was addedand the mixture homogenized by high-speed mixing (21,000 rpm) for 1minute. The crude emulsion was then refined by microfluidization (5,000psi) for 1 minute. The resulting emulsion was then filtered with a 0.45μm nylon filter and stored at 4° C.

PFOB additive emulsion. To a 50 mL falcon tube were added 13.42 mLnormal saline, 10 mM M1H10F8, and 3.4 mL PFOB. This was vortexed for 1minute and sonicated for 30 minutes with heating. The resulting solutionwas allowed to cool to room temperature and then 0.18 mL propofol wasadded and the mixture homogenized by high-speed mixing (21,000 rpm) for1 minute. The crude emulsion was then refined by microfluidization(5,000 psi) for 1 minute. The resulting emulsion was then filtered witha 0.45 μm nylon filter and stored at 4° C.

Analysis Section No. 2

Propofol is the most common agent for induction of general anesthesia inthe United States. In addition, it is commonly used for maintenance ofanesthesia as well as sedation in the operating room and intensive careunit. The formulation available clinically (Diprivan®) is a lipidemulsion of 1% propofol with 10% soybean oil, 1.2% egg yolk lecithin,and 2.25% glycerol. This formulation is clinically effective but it doeshave several drawbacks, including the allowance of microbial growth,effects related to hyperlipidemia (elevated triglycerides and propofolinfusion syndrome), and pain on injection. Although minor, anaphylaxishas also been of concern. Because of these issues, many attempts havebeen made to reformulate the drug. These attempts have included theaddition of preservatives and anti-microbials, variations of oil andlecithin content, changes in size of triglycerides, and a host of newsolvents. In this set of experiments, we studied four propofolnanoemulsions using novel surfactants, and compared their anestheticeffects to those of Diprivan® in rats. In addition, we tested whether abolus of Intralipid® administered during the recovery phase wouldaccelerate emergence from anesthesia.

All animal studies were approved by the University of Wisconsin AnimalCare and Use Committee, Madison, Wisconsin. Experiments to measure lossand recovery of the righting reflex were carried out in six maleSpraque-Dawley rats weighing approximately 280 g. The rats were receivedfrom the supplier with a surgically-implanted jugular catheter. Fivedifferent propofol formulations were tested: 1) Diprivan®; 2) lipid-freeformulation using a semifluorinated surfactant and egg lecithindesignated L3; 3) lipid-free formulation using a semifluorinatedsurfactant designated B8; 4) lipid-free formulation using asemifluorinated surfactant and PFOB designated F8; 5) lipid-freeformulation using only Lipoid E80 designated L80. For each formulation,five different bolus doses ranging from 5-15 mg/kg were administered 5times each over 20 s using a syringe pump. In all cases, the ratsreceived only one dose of anesthetic per day. Subsequently, theanesthetic effects of B8 and Diprivan® were tested for reversibilityutilizing an Intralipid® bolus after an induction dose. Intralipid®doses from 3.75-15 ml/kg were tested in combination with 15 mg/kg of B8or Diprivan®.

Four of the five formulations showed efficacy in causing loss of therighting reflex. The one exception was L80, which did not induceanesthesia at doses up to 15 mg/kg. The other formulations all inducedLORR, all animals regained righting reflex, and no ill effects wereobserved during or after the anesthetic period. To compare potency ofinduction doses between the formulations, time to recovery of rightingreflex was plotted vs log dose. For each data set, the linear regressionline crossing the x-axis was considered the threshold dose for causingloss of righting reflex. There were no significant differences betweenthe threshold doses for the four drugs: 5.2, 6.0, 5.5, and 6.8 mg/kg forDiprivan®, L3, B8, and F8 respectively. Using a similar method forevaluating the effect of Intralipid® bolus, time to recovery of rightingreflex was plotted vs log dose with the slope of the linear regressionline representing clearance. A 39% (p=0.014) and 51% (p=0.046) reductionin slope were seen for Diprivan® and B8, respectively.

The three lipid-free fluoropolymer-based formulations of propofol allshowed similar efficacy, potency, and duration in producing andmaintaining anesthesia with bolus dosing, comparable to Diprivan.Additionally, clearance of propofol from its effect site was acceleratedwith Intralipid® after an induction dose. These lipid free formulationshave the potential to avoid complications related to microbial growthand hyperlipidemia that are seen with the currently availableformulation of propofol. Further study is indicated to determinetoxicity and side effect profiles of these novel surfactant formulationsbefore they can be considered for clinical use.

Introduction

Propofol is commonly used for induction and maintenance of generalanesthesia, and for sedation in the operating room and intensive careunit. Initially tested for administration in Cremophor EL, theformulation now available clinically (Diprivan®; AstraZeneca, London,United Kingdom) is a lipid-based emulsion consisting of 1% propofoltogether with 10% soybean oil, 1.2% egg yolk lecithin, and 2.25%glycerol. (Baker) This formulation is clinically effective but it doeshave several drawbacks, including emulsion instability (Park, Han), theopportunity for microbial growth (Bennett, Wachowski, Langevin), effectsrelated to hyperlipidemia (elevated triglycerides and propofol infusionsyndrome) (Wolf, Wong, Mayette, Rosen), and pain on injection. (Tan)Although rare, anaphylaxis has also been of concern. (Laxenaire, DeLeon-Casasola)

Many different formulations of propofol have been studied in an attemptto remedy these issues. Preservatives and anti-microbial agents such asEDTA and sodium metabisulfite have been added. (Baker, Thompson) The oiland lecithin contents have been varied. (Song) Different sizes oftriglycerides and new solvents have been tested. (Rau, Egan) Propofol'sinteraction with local endothelium, caused either by free propofol inthe aqueous phase or by the drug bein released rapidly from the oilphase, has been implicated in causing pain with injection. (Damitzl,Dubey, Ohmizo) Therefore, alternative emulsions have been developed tominimize the free concentration in an attempt to minimize this problem.(Cai, Damitz2) Prodrugs of propofol such as fospropofol are clinicallyavailable and have decreased pain on injection but have slower onset andprolonged elimination half-life. (Pergolizzi) Recently, Aquafol (DaewonPharmaceutical Co., Ltd., Seoul, Korea), a 1% propofol microemulsionwith 10% purified poloxamer 188 (PP188) and 0.7% poly-ethylene glycol660 hydroxystearate (using no lipid), has become clinically available insome parts of the world. (Jung, Sim, Lee)

In this set of experiments, we studied in rats three propofolnanoemulsions prepared using novel semifluorinated surfactants, andcompared their anesthetic effects to formulations containing only theclassical surfactant Lipoid E80 and the clinically used formulation ofDiprivan®. Semifluorinated-surfactant based emulsions have been studiedas blood substitutes and also used for intravenous drug delivery,including intravenous delivery of the inhalational anestheticsevoflurane. (Riess1, Riess2, Krafft, Fast) Semifluorinated surfactantswere chosen for their unique architecture (lipophilic and fluorophilicblocks) and designed to eliminate the need to add soybean oil to theemulsion. The lipophilic moiety was intended to stabilize the dissolvedpropofol, and the fluorophilic moiety to stabilize the nanodropletemulsion.

In addition to testing these emulsions for stability and efficacy, wetested whether a post-induction bolus of Intralipid® would acceleraterecovery from the anesthetic effects of propofol, a highly lipid-solubledrug, as it does for the toxic effects of several lipid-soluble drugsincluding bupivacaine.(Weinberg/VadeBoncouer) The rationale for thesestudies is that the octanol:water partition coefficient (log P) ofpropofol is 3.79 (Babu), which makes it even more lipid soluble thanbupivacaine (log P 3.41). (Hansch) If the lipid solubility of propofolcauses a decreased effect site concentration with lipid infusion throughpartitioning, then the duration of anesthesia caused by propofol may bereduced with a lipid infusion.

Methods

Experiments were carried out in two phases. The purpose of the firstphase was to demonstrate the efficacy of L3, B8, and F8 to produceanesthesia; to determine a threshold dose for causing loss of rightingreflex (LORR) in the rat; and to test for adverse effects of thedrugs—all in comparison to Diprivan®. The purpose of the second phasewas to determine the effect of a bolus of Intralipid® on the anestheticeffects of B8 and Diprivan®.

Surfactants

The semifluorinated surfactants M1 H10-O-F3 and M1pH10F8 were used inthe L3 and B8 emulsions, respectively, and the classical surfactantM5diH10, and the semifluorinated surfactant M1H10F8 were used in the F8emulsion. These emulsions were synthesized as previously reported.(Tucker)

Structure of semifluorinated surfactants M1 H10-O-F3 (L3) and M1μH10F8(B8).

Structure of classical surfactant M5diH10 and semi-fluorinatedsurfactant M1H10F8 (F8).

Emulsions

All emulsions were prepared by combining the surfactant, additives andpropofol in water (with salt or glycerol for isotonicity). B8, L3, andM5diH10 surfactant solutions were prepared as 25 mg/mL solutions bydirect dilution of lyophilized solid in sterile, normal saline solutionto a total volume of 16.82 mL. The emulsion L80, containing only LipoidE80, from Lipoid GmbH (Ludwigshafen, Germany), were prepared bydissolution of Lipoid E80 at a concentration of 12 mg/mL in 16.82 mLdouble-distilled water with added glycerol for isotonicity. L3 alsocontained 12 mg/mL Lipoid E802. The F8 surfactant solution was preparedas a 16 mg/mL solution in 13.42 mL normal saline with 3.4 mLperfluorooctyl bromide (PFOB) from Synquest Labs (Alachua, Fla.). Thesolutions were sonicated until completely dissolved. A 0.18 mL volume of2,6-diisopropylphenol from Sigma Aldrich Co. (Milwaukee, Wis.) was addedto the polymer solutions for a total volume of 17 mL. The high-speedhomogenizer (Power Gen 500) from Fisher Scientific (Hampton, N.H.) andthe microfluidizer (model 110 S) from Microfluidics Corp. (Newton,Mass.) were first cleaned with 70% and 100% ethanol, followed by 70% and100% methanol, and finally with three rinses of Millipore water. Onceprepared, each emulsion mixture was then homogenized with the high-speedhomogenizer for 1 min at 21000 rpm at room temperature. The crudeemulsion was then microfluidized for 1 min at 5000 psi with the coolingbath kept at 10° C. The final emulsion was then filtered with a 30 mmdia., 0.45 pm nylon filter and stored in 45 mL plastic centrifuge tubesfrom Corning Inc. (Corning, N.Y.) at 4° C. After preparation andfiltration of the emulsions, the emulsion droplet sizes were measured bydynamic light scattering (NICOMP 380ZLS) from Particle Sizing Systems(Santa Barbara, Calif.). An aliquot of the emulsion, approximately 150μL, was diluted in 3 mL of Millipore water to achieve an intensityfactor range of 300-350. Each measurement was run for 5 minutes at roomtemperature and repeated in triplicate. The data were analyzed byGaussian analysis and reported as a volume-weighted average diameter.The emulsion errors for all polymers were taken as an average of thestandard deviations of each individual measurement.

Animal Studies

All animal studies were approved by the University of Wisconsin AnimalCare and Use Committee, Madison, Wis., and were performed in accordancewith the guidelines laid out in the Guide for the Care and Use ofLaboratory Animals published by the National Research Council.

Phase I and 2 experiments were carried out in six male Spraque-Dawleyrats (Harlan Spraque-Dawley, Inc., Indianapolis, Ind.) weighingapproximately 280 g.

The rats were received from the supplier with a surgically implantedjugular catheter. In all cases, the rats received only one dose ofanesthetic per day.

In phase I, experiments to measure loss and recovery of righting reflexwere conducted using five different propofol formulations: 1) Diprivan®;2) L3; 3) B8; 4) F8; and 5) L80. For each of the first threeformulations, five different doses (5-15 mg/kg) were administered fivetimes each. For F8 each of the five doses was administered three timeseach. For L80, the highest dose (15 mg/kg) was tested five times. Sincethis dose did not lead to LORR, a limited number of lower doses werestudied, and none led to LORR. Dosing was based on previously publisheddata for propofol in rats. (Adam, Glen, Brammer).

The propofol emulsions were administered by first weighing the rat andthen restraining it with a towel. The plug placed at the end of thecatheter was then removed and replaced with a 23-gauge blunt tip needleconnected to an insulin-type syringe. To remove the heparin-based fillsolution and check that no blockage was obstructing the catheter, thesyringe plunger was slowly withdrawn until blood filled the catheter.The 23-gauge blunt tip needle was then removed and the catheter wasconnected using a 23-gauge connector tip to the tubing and syringecontaining the propofol emulsion to be tested. The rat was placed in atransparent cage for observation. Forty μl of the emulsion,corresponding to the volume of the catheter was injected to prime thecatheter and then the administration of the emulsion was started. Theemulsion injection rate was controlled through an infusion pump (11plus; Harvard Apparatus, Holliston, Mass.). A bolus dose was deliveredover 20 s regardless of the dose. LORR was evaluated by rolling the ratonto its back and observing whether the animal was able to right itself.The times to achieve and to recover from LORR were recorded. When therat completely recovered from LORR, the catheter was flushed with 40 μlof 0.9% saline solution to remove the residual emulsion and thenrefilled with 40 μl of a heparin-based fill solution. The end of thecatheter was sealed with a sterile plug.

In phase 2, experiments to measure the effect of an Intralipid® bolus onthe anesthetic effects of Diprivan® and B8 were conducted. For both,three different doses (7.5-15 mg/kg) were administered five times each.The three doses chosen reliably caused LORR with both emulsions asdetermined in phase 1. In the same fashion as in phase 1, the rats wererestrained and connected to the tubing and syringe containing thepropofol emulsion. Procedures for bolus dose administration anddetermination of loss and recovery of righting reflex were carried outas in phase 1. Sixty seconds after starting the bolus propofol dose, theanimals' catheters were connected to tubing and a syringe containingIntralipid® (20% lipid emulsion). A bolus of Intralipid® was thenadministered over 60 seconds. For the highest propofol doseadministered, three different Intralipid® bolus doses were administeredfive times each (3.75-15 ml/kg). For the two decreased doses of propofolonly the highest dose of Intralipid® was administered. Dosing was basedon previously published data utilizing lipid for treatment of drugtoxicity in rats. (Jamaty, Perez, Hiller, Di Gregorio,Weinberg/VadeBoncouer)

Statistics

Comparisons were made using unpaired t-tests. Differences wereconsidered significant at a level of p<0.05.

Results Emulsion Stability

In an effort to eliminate any added soybean oil from the developedpropofol emulsions, semi-fluorinated surfactants were investigated fortheir ability to solubilize propofol (hydrophobic moiety) and stabilizethe nanodroplet (fluorinated moiety). It was found that B8formulation-containing only M1pH10F8 surfactant, as shown in FIG. 5, andpropofol dispersed in normal saline-formed an emulsion stable for 42days with a growth rate of 3.60 nm/day. A similar formulation usingM1H10-O-F3 failed to produce a stable emulsion. As shown in FIG. 5, thestable formulation L3 utilized M1H10-O-F3 and Lipoid E80 as equimolarco-surfactants, was stable for 406 days, with a growth rate of 0.02nm/day.

The results of further investigations into the emulsion formulation areshown in FIG. 6. It was found that the classical(hydrophilic-lipophilic) surfactant M5diH10 did emulsify propofol andwas stable for 21 days with a growth rate of 12.52 nm/day, but theemulsion rapidly grew in size. Lipoid E80—the surfactant used inDiprivan® —also formed stable emulsions, when glycerol instead of saltwas used to achieve isotonicity. The emulsion was stable for 154 dayswith a growth rate of 0.50 nm/day . The final emulsion formulationinvestigated utilized a linear, semifluorinated surfactant M1H10F8,structurally similar to L3, but incorporated a fluorinated stabilizer(perfluorooctyl bromide, PFOB) instead of a phospholipid co-surfactant.This emulsion was found to be stable for 119 days with a growth rate of1.65 nm/day.

Phase 1-Emulsion Efficacy

The L80 caused only mild sedation and failed to cause LORR up to apropofol dose of 15 mg/kg.

The five bolus doses tested of Diprivan®, L3, B8 and F8 were 5, 6.25,7.5, 10 and 15 mg/kg. All three formulations proved effective in causingLORR, as shown in FIG. 7. F8 proved to be effective at inducinganesthesia, but only at higher doses (compared to B8, L3 and Diprivan)and with prolonged duration at the highest, 15 mg/kg, dose.

Data are plotted as time to loss or recovery of righting reflex as afunction of drug dose, expressed on a mg/kg basis for the propofolcomponent of the nanoemulsion. The x-axis intersection is the calculatedthreshold dose for inducing LORR as a surrogate forunconsciousness.(Liao)

There was no significant difference between threshold doses of Diprivan®and B8. The L3 threshold dose was slightly, but significantly higher. Noill effects were seen in the rats acutely, or after >10 doses over a twoweek period.

Table I shows that for the three doses that reliably caused LORR, timeto recovery of righting reflex was significantly longer for Diprivan®compared to L3 and B8.

TABLE I Duration of Anesthesia versus Dose for Diprivan, L3, and B8Duration of anesthesia (s) 7.5 mg/kg 10 mg/kg 15 mg/kg Diprivan ® 157.60± 43.59 342.83 ± 155.95  668.8 ± 60.35 L3  65.33 ± 33.97 220.20 ± 49.30554.60 ± 45.52 B8 189.67 ± 168.94  190.6 ± 104.11 548.60 ± 63.03

For 7.5 mg/kg doses, duration of anesthesia of L3 was significantlyshorter (p=0.005) than Diprivan®; B8 was not significantly differentthan Diprivan® or L3. For 10 mg/kg doses, duration of anesthesia of L3and B8 were significantly shorter (p=0.0034 and p=0.0067, respectively)than Diprivan®; B8 and L3 were not significantly different from oneanother. For 15 mg/kg doses, duration of anesthesia of L3 and B8 weresignificantly shorter (p=0.0108 and p=0.0151, respectively) thanDiprivan®; B8 and L3 were not significantly different from one another.

Phase 2-Intralipid® Studies

The three bolus doses tested of Diprivan® and B8 were 7.5, 10, and 15mg/kg.

FIG. 8 provides a plot for Diprivan® with 15 ml kg⁻¹ Intralipid®. Thedata are plotted as time to recovery of righting reflex as a function ofdrug dose, expressed on a mg/kg basis for the propofol component of thenanoemulsion. Using the slope of the trendline to represent rate ofclearance, the lower the slope the more rapid the clearance of propofolfrom its effect site (faster recovery of righting reflex for a givendose).

The slope of the line using Diprivan® followed by Intralipid® is 39%less than the slope of the line using Diprivan® alone. This is asignificant difference (p=0.014). There was greater reduction induration of anesthesia for higher doses (10, 15 mg/kg) and virtually nochange for the 7.5 mg/kg dose.

FIG. 9 provides a plot for B8 with 15 ml kg⁻¹ Intralipid®. The data areplotted as time to recovery of righting reflex as a function of drugdose, expressed on a mg/kg basis for the propofol component of thenanoemulsion.

Again, a reduction (51%) in the slope of the trend line was seen usingB8 with Intralipid®. This is significantly different (p=0.046). However,most of this reduction was due to the 15 mg/kg dose with little, if any,reduction for the 7.5 and 10 mg/kg doses.

FIG. 10 provides a plot for B8 and Diprivan® with Intralipid®. The dataare plotted as time to return of righting reflex vs Intralipid® dose.Large doses (15 mg/kg) of B8 and Diprivan® were administered incombination with decreasing doses of Intralipid® (15, 7.5, and 3.75ml/kg). Error bars are added.

The 15 ml/kg dose of Intralipid® caused a significant reduction induration of anesthesia for B8 (p=0.0008), and a noticeable but notsignificant decrease for Diprivan® (p=0.0632). The smaller doses (3.75and 7.5 ml/kg) of Intralipid® cause little, if any, reduction comparedto 15 mg/kg doses without the addition of Intralipid®.

Discussion

These novel fluoropolymer emulsions of propofol, L3, B8, and F8 wereable to reliably induce anesthesia in rats. There were no ill effectseither acutely or after more than 10 administrations over a 2-3 weekperiod. The threshold dose of the emulsion containing only fluoropolymerand propofol, B8, was not significantly different than that of Diprivan®in rats; the threshold dose of L3 and F8 were only slightly higher. Inregards to duration of anesthesia after a bolus dose, B8 and L3 were notsignificantly different across all doses. For higher doses (10 and 15mg/kg) B8 and L3 produce a significantly shorter duration of anesthesiathan Diprivan®, and F8 longer. This may be due to decreasedbioavailability or slower release of propofol in the B8 and L3emulsions, and especially in F8, compared to Diprivan®.

Interestingly, the formulation containing only propofol and Lipoid E80did not cause LORR even at high doses. Additionally, the L3 emulsion,which contained Lipoid E80, required a higher threshold dose to causeLORR than B8, which did not contain the surfactant. If Lipoid E80 is afactor in the bioavailability of propofol from the emulsions, it may bepossible to vary its concentration to affect release of the drug. Thiscould have implications for pain on injection as well as hemodynamicinstability after bolus dosing.

These 3 formulations of propofol all showed similar efficacy, potency,and duration in producing and maintaining anesthesia with bolus dosing.Additionally, clearance of propofol from its effect site can beaccelerated with Intralipid® after an induction dose. This effect wasobserved even with the lipid-based formulation (Diprivan®), but wasstronger for the lipid-free formulation B8. The effect was mostsignificant when a high dose of drug (15 mg/kg) was followed by a highvolume of lipid (15 ml/kg).

Several mechanisms have been proposed for lipid rescue in toxicity frombupivacaine as well as other drugs. The most commonly cited is via“partitioning” in which the lipid acts as an intravascular “sink,”causing decreased concentrations of drug at the effect site. A secondproposed mechanism is the accelerated shunting of the drug to its siteof metabolism, which is typically the liver for lipid-soluble drugs.(Weinberg, Weinberg/VadeBoncouer, Weinberg/Ripper) In either case, thereis increased clearance of the drug from the effect site, which in thecase of propofol is GABAa receptors in the CNS. We see this in thedecreased slope of the linear regression lines when propofoladministration is followed by Intralipid® bolus. Partitioning has beenproposed as a mechanism for several lipid soluble drugs (localanesthetics, calcium channel blockers, beta blockers, etc.) whosetoxicity has been treated with lipid infusion. (Jamaty, Perez) Thiscould partially explain our results in that propofol, log P(octanol:water partition coefficient) 3.79 (Babu), is more lipid solublethan bupivacaine, which has a log P of 3.41.(Hansch)

It would follow then that a high lipid dose would shorten duration ofanesthesia more than a lower dose, but we saw a lack of effect with 7.5and 3.75 ml/kg doses of Intralipid®. There is some evidence that inbupivacaine toxicity, lipid works to reverse inhibition of fatty acidmetabolism in cardiac muscle. (Weinberg) It may be possible thatIntralipid® interferes with propofol binding to the GABAa receptor, andthat there is a threshold concentration required to see this effect,which the 7.5 and 3.75 ml/kg doses are not large enough to reach.

The 15 ml/kg dose of Intralipid® that was found to be effective in thisstudy is relatively large. However, it is possible that lower volumeswould be effective in a human as compared to the rat. Induction ofanesthesia in humans typically requires 1-2 mg/kg, but in rats that doseis 5-10 times higher. A similar reduction in Intralipid® dose to 1.5-3ml/kg or less may have particular clinically utility.

REFERENCES

Baker M T, Naguib M: Propofol the challenges of formulation.Anesthesiology 2005; 103:860-76

Park J W, Park E S, Chi S C, Kil H Y, Lee K H: The effect of lidocaineon the globule size distribution of propofol emulsions. Anesth Analg2003; 97:769-71

Bennett S N, McNeil M M, Bland L A, Arduino M J, Villarino M E, PerrottaD M, Burwen D R, Welbel S F, Pegues D A, stroud I, Zeitz P S, Jarvis WR: Postoperative infections traced to contamination of an intravenousanesthetic, propofol. N Engl J Med 1995; 333:147-54

Wachowski I, Jolly D T, Hrazdil J, Galbraith J C, Greacen M, Clanachan AS: The growth of microorganisms in propofol and mixtures of propofol andlidocaine Anesth Analg 1999; 88:209-12

Langevin P B, Gravenstein N, Doyle T J, Roberts S A, Skinner S, LangevinS O, Gulig P A: Growth of Staphylococcus aureus in Diprivan andIntralipid: Implications on the pathogenesis of infections.Anesthesiology 1999; 91:1394-400

Wolf A, Weir P, Segar P, Stone J, Shield J: Impaired fatty acidoxidation in propofol infusion syndrome. Lancet 2001; 357:606-7

Wong J M: Propofol infusion syndrome. Am J Ther 2010; 17:487-91

Mayette M, Gonda J, Hsu J L, Mihm F G: Propofol infusion syndromeresuscitation with extracorporeal life support: a case report and reviewof the literature. Ann Intensive Care 2013; 3:32

Rosen D J, Nicoara A, Koshy N, Wedderburn R V: Too much of a good thing?Tracing the history of the propofol infusion syndrome. J Trauma 2007;63:443-7

Tan C H Onsiong M K: Pain on injection of propofol. Anaesthesia 1998;53:468-76

Laxenaire M C, Gueant J L, Bermejo E, Mouton C: Anaphylactic shock dueto propofol. Lancet 1988; 2:739-40

De Leon-Casasola O A, Weiss A, Lema M J: Anaphylaxis due to propofol.Anesthesiology 1992; 77:384-6

Han J, Davis S S, Washington C: Physical properties and stability of twoemulsion formulations of propofol. Int J Pharm 2001; 215: 207-20

Thompson K A, Goodale D B: The recent development of propofol(DIPRIVAN). Intens Care Med 2000; 26 (Suppl. 4): S400L 404

Song D1, Hamza M, White P F, Klein K, Recart A, Khodaparast 0: Thepharmacodynamic effects of a lower-lipid emulsion of propofol: acomparison with the standard propofolemulsion. Anesth Analg 2004;98:687-91

Rau J, Roizen M F, Doenicke A W, O′Connor M F, Strohschneider U:Propofol in an emulsion of long- and medium chain triglycerides: theeffect on pain. Anesth Analg 2001; 93:382-4

Egan T D, Kern S E, Johnson K B, Pace N L: The pharmacokinetics andpharmacodynamics of propofol in a modified cyclodextrin formulation(Captisol) versus propofol in a lipid formulation (Diprivan): anelectroencephalographic and hemodynamic study in a porcine model. AnesthAnalg 2003; 97:72-9

Damitz R, Chauhan A: Rapid dissolution of propofol emulsions under sinkconditions. Int J Pharm 2015; 481:47-55

Dubey P K, Kumar A: Pain on injection of lipid-free propofol andpropofol emulsion containing medium-chain triglyceride: A comparativestudy. Anesth Analg 2005; 101:1060-2

Ohmizo H, Obara S, Iwama H: Mechanism of injection pain with long andlong-medium chain triglyceride emulsive propofol. Can J Anaesth 2005;52: 595-9

Cai W, Deng W, Yang H, Chen X, Jin F: A propofol microemulsion with lowfree propofol in the aqueous phase: formulation, physicochemicalcharacterization, stability and pharmacokinetics. Int J Pharm 2012;436:536-44

Damitz R, Chauhan A: Kinetically stable propofol emulsions with reducedfree drug concentration for intravenous delivery. Int J Pharm 2015;486:232-41

Pergolizzi Jr J V, Gan, T J, Plavin S, Labhsetwar S, Taylor R:Perspectives on the role of fospropofol in the monitored anesthesia caresetting. Anesthesiol Res Pract 2011; 458920

Jung J A, Choi B M, Cho S H, Choe S M, Ghim J L, Lee H M, Roh Y J, Noh GJ: Effectiveness, safety, and pharmacokinetic and pharmacodynamicscharacteristics of microemulsion propofol in patients undergoingelective surgery under total intravenous anaesthesia. Br J Anaesth 2010;104:563-76

Sim, J Y, Lee S H, Park D Y, Jung J A, Ki K H, Lee D H, Noh G J: Pain oninjection with microemulsion propofol. Br J Clin Pharmacol 2009; 67:316-25

Lee E, Lee S, Park D, Ki K, Lee E, Lee D, Noh G: Physicochemicalproperties, pharmacokinetics and pharmacodynamics of a reformulatedmicroemulsion propofol in rats. Anesthesiology 2008; 109:436-47

Riess J G. Oxygen carriers (“blood substitutes”)-raison d′etre,chemistry, and some physiology. Chem Rev 2001; 101:2797-920

Riess J G. Highly fluorinated systems for oxygen transport, diagnosisand drug delivery. Colloids Surf A 1994; 84:33-48

Krafft M P. Fluorocarbons and fluorinated amphiphiles in drug deliveryand biomedical research. Adv Drug Deliv Rev 2001; 47:209-28

Fast J P, Perkins M G, Pearce R A, Mecozzi S: Fluoropolymer-basedemulsions for the intravenous delivery of sevoflurane. Anesthesiology2008; 109:651-6

Weinberg G L, VadeBoncouer T, Ramaraju G A, Garcia-Amaro M F, Cwik M J:Pretreatment or resuscitation with a lipid infusion shifts thedose-response to bupivacaine-induced asystole in rats. Anesthesiology1998; 88:1071-5

Babu M K, Godiwala T N: Toward the development of an injectable dosageform of propofol: preparation and evaluation of propofol-sulfobutylether 7-beta-cyclodextrin complex. Pharm Dev Technol 2004; 9: 265-75

Hansch, C., Leo, A., D. Hoekman. Exploring QSAR-Hydrophobic, Electronic,and Steric Constants. Washington, D.C.: American Chemical Society 1995.,p. 159

Tucker, W. B.; McCoy, A. M.; Fix, S. M; Stagg, M. F.; Murphy, M. M.;Mecozzi, S. Synthesis, physicochemical characterization, andself-assembly of linear, dibranched and miktoarm semifluorinatedtriphilic polymers. J. Polym. Sci. A: Polym. Chem. 2014, 52, 3324-3336.

Adam H K, Glen J B, Hoyle P A: Pharmacokinetics in laboratory animals ofICI 35 868, a new i.v. anaesthetic agent. Br J Anaesth 1980; 52:743-6

Glen J B, Hunter S C: Pharmacology of an emulsion formulation of ICI 35868. Br J Anaesth 1984; 56:617-26

Brammer A, West C D, Allen S L: A comparison of propofol with otherinjectable anaesthetics in a rat model for measuring cardiovascularparameters. Lab Anim 1993; 27:250-7

Jamaty C, Bailey B, Larocque A, Notebaert E, Sanogo K: Lipid emulsionsin the treatment of acute poisoning: a systematic review of human andanimal studies. Clin Toxicol (Phila) 2010; 48:1-27

Perez E, Bania T C, Medlej K, Chu J: Determining the optimal dose ofintravenous fat emulsion for the treatment of severe verapamil toxicityin a rodent model. Acad Emerg Med 2008; 15:1284-9

Hiller D B, Di Gregorio G, Kelly K, Ripper R, Edelman L, Boumendjel R,Drasner K, Weinberg G L: Safety of high volume lipid emulsion infusion afirst approximation of LD50 in rats. Reg Anesth Pain Med 2010; 35:140-4

Di Gregorio G, Schwartz D, Ripper R, Kelly K, Feinstein D L, Minshall RD, Massad M, On C, Weinberg G L; Lipid emulsion in superior tovasopressin in a rodent model of resuscitation from toxin-inducedcardiac arrest. Crit Care Med 2009; 37:993-999

Liao M, Sonner J M, Husain S S, Miller K W, Jurd R, Rudolph U, Eger El:R (+) etomidate and the photoactivable R (+) azietomidate havecomparable anesthetic activity in wild-type mice and comparablydecreased activity in mice with a N265M point mutation in thegamma-aminobutyric acid receptor B3 subunit. Anesth Analg 2005;101:131-5

Weinberg G L: Lipid emulsion infusion resuscitation for local anestheticand other drug overdose. Anesthesiology 2012; 117:180-7

Weinberg G, Ripper R, Feinstein D L, Hoffman W: Lipid emulsion infusionrescues dogs from bupivacaine-induced cardiac toxicity. Reg Anesth PainMed 2003; 38:198-202

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references cited throughout this application, for example patentdocuments including issued or granted patents or equivalents; patentapplication publications; and non-patent literature documents or othersource material; are hereby incorporated by reference herein in theirentireties, as though individually incorporated by reference, to theextent each reference is at least partially not inconsistent with thedisclosure in this application (for example, a reference that ispartially inconsistent is incorporated by reference except for thepartially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used asterms of description and not of limitation, and there is no intention inthe use of such terms and expressions of excluding any equivalents ofthe features shown and described or portions thereof, but it isrecognized that various modifications are possible within the scope ofthe invention claimed. Thus, it should be understood that although thepresent invention has been specifically disclosed by preferredembodiments, exemplary embodiments and optional features, modificationand variation of the concepts herein disclosed may be resorted to bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of this invention as defined by theappended claims. The specific embodiments provided herein are examplesof useful embodiments of the present invention and it will be apparentto one skilled in the art that the present invention may be carried outusing a large number of variations of the devices, device components,methods steps set forth in the present description. As will be obviousto one of skill in the art, methods and devices useful for the presentmethods can include a large number of optional composition andprocessing elements and steps.

When a group of substituents is disclosed herein, it is understood thatall individual members of that group and all subgroups, including anyisomers, enantiomers, and diastereomers of the group members, aredisclosed separately. When a Markush group or other grouping is usedherein, all individual members of the group and all combinations andsubcombinations possible of the group are intended to be individuallyincluded in the disclosure. When a compound is described herein suchthat a particular isomer, enantiomer or diastereomer of the compound isnot specified, for example, in a formula or in a chemical name, thatdescription is intended to include each isomers and enantiomer of thecompound described individual or in any combination. Additionally,unless otherwise specified, all isotopic variants of compounds disclosedherein are intended to be encompassed by the disclosure. For example, itwill be understood that any one or more hydrogens in a moleculedisclosed can be replaced with deuterium or tritium. Isotopic variantsof a molecule are generally useful as standards in assays for themolecule and in chemical and biological research related to the moleculeor its use. Methods for making such isotopic variants are known in theart. Specific names of compounds are intended to be exemplary, as it isknown that one of ordinary skill in the art can name the same compoundsdifferently.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural reference unless thecontext clearly dictates otherwise. Thus, for example, reference to “acell” includes a plurality of such cells and equivalents thereof knownto those skilled in the art, and so forth. As well, the terms “a” (or“an”), “one or more” and “at least one” can be used interchangeablyherein. It is also to be noted that the terms “comprising”, “including”,and “having” can be used interchangeably. The expression “of any ofclaims XX-YY” (wherein XX and YY refer to claim numbers) is intended toprovide a multiple dependent claim in the alternative form, and in someembodiments is interchangeable with the expression “as in any one ofclaims XX-YY.”

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, the preferred methodsand materials are now described. Nothing herein is to be construed as anadmission that the invention is not entitled to antedate such disclosureby virtue of prior invention.

Every formulation or combination of components described or exemplifiedherein can be used to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, atemperature range, a time range, or a composition or concentrationrange, all intermediate ranges and subranges, as well as all individualvalues included in the ranges given are intended to be included in thedisclosure. As used herein, ranges specifically include the valuesprovided as endpoint values of the range. For example, a range of 1 to100 specifically includes the end point values of 1 and 100. It will beunderstood that any subranges or individual values in a range orsubrange that are included in the description herein can be excludedfrom the claims herein.

As used herein, “comprising” is synonymous with “including,”“containing,” or “characterized by,” and is inclusive or open-ended anddoes not exclude additional, unrecited elements or method steps. As usedherein, “consisting of” excludes any element, step, or ingredient notspecified in the claim element. As used herein, “consisting essentiallyof” does not exclude materials or steps that do not materially affectthe basic and novel characteristics of the claim. In each instanceherein any of the terms “comprising”, “consisting essentially of” and“consisting of” may be replaced with either of the other two terms. Theinvention illustratively described herein suitably may be practiced inthe absence of any element or elements, limitation or limitations whichis not specifically disclosed herein.

One of ordinary skill in the art will appreciate that startingmaterials, biological materials, reagents, synthetic methods,purification methods, analytical methods, assay methods, and biologicalmethods other than those specifically exemplified can be employed in thepractice of the invention without resort to undue experimentation. Allart-known functional equivalents, of any such materials and methods areintended to be included in this invention. The terms and expressionswhich have been employed are used as terms of description and not oflimitation, and there is no intention that in the use of such terms andexpressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the invention claimed.Thus, it should be understood that although the present invention hasbeen specifically disclosed by preferred embodiments and optionalfeatures, modification and variation of the concepts herein disclosedmay be resorted to by those skilled in the art, and that suchmodifications and variations are considered to be within the scope ofthis invention as defined by the appended claims.

1. An emulsion for delivery of a therapeutic agent, said emulsion comprising: an aqueous solution; semi-fluorinated block copolymers; wherein each of said semi-fluorinated block copolymers independently comprises a hydrophilic block, a hydrophobic block and a fluorophilic block; wherein said hydrophobic block of each of said semi-fluorinated block copolymers is provided between said fluorophilic block and said hydrophilic block; said therapeutic agent comprising a hydrophobic compound; and a perhalogenated fluorous compound; said emulsion comprising a continuous phase and a dispersed phase, wherein said continuous phase comprises said aqueous solution and said dispersed phase comprises said semi-fluorinated block copolymers, said therapeutic agent and said perhalogenated fluorous compound. 2-4. (canceled)
 5. The emulsion of claim 1, wherein said fluorophilic block, said hydrophilic block, or both, of each of said semi-fluorinated block copolymers is a polymer terminating group.
 6. (canceled)
 7. The emulsion of claim 1 any of claims 1 6, wherein said fluorophilic block, said hydrophilic block, or both, of each of said semi-fluorinated block copolymers is directly linked to said hydrophobic group.
 8. (canceled)
 9. The emulsion of claim 1, wherein said fluorophilic block, said hydrophilic block or both are independently linked to said hydrophobic block via a linking moiety selected from the group consisting of an ether group, a carbamate group, an amide group, an alkylene group, amino group or any combination of these.
 10. The emulsion of claim 1, wherein each of said fluorophilic blocks of said semi-fluorinated block copolymers is independently a fluorocarbon moiety having between 3 to 31 carbon-fluorine bonds.
 11. (canceled)
 12. (canceled)
 13. The emulsion of claim 1, wherein said hydrophilic blocks of said semi-fluorinated block copolymers are independently selected from the group consisting of a polyoxygenated polymer block, a polysaccharide block, a chitosan derivative block, and a poly(ethylene glycol) block.
 14. (canceled)
 15. The emulsion of claim 1, wherein each said hydrophobic blocks of said semi-fluorinated block copolymers is independently selected from the group consisting of a C₅-C₂₀ alkylene group, a poly (c-caprolactone) block, a poly(lactic acid) block; a poly(propylene glycol) block; a poly(amino acid) block; a poly(ester) block and poly(lactic-co-glycolic acid). 16-18. (canceled)
 19. The emulsion of claim 1, wherein each of said semi-fluorinated block copolymers independently has the formula (FX2):

wherein m is 0 or 1 and n is 0 or 1; wherein q is an integer selected from the range of 10 to 300, o is an integer selected from the range of 5 to 20, and p is an integer selected from the range of 3 to 15; wherein R¹ is hydrogen, methyl, C₁-C₁₀ alkyl, C₃-C₁₀ cycloalkyl, C₅-C₁₀ aryl, C₅-C₁₀ heteroaryl, C₁-C₁₀ alkoxy or C₁-C₁₀ acyl; wherein R² is hydrogen, halo or C₁-C₅ alkyl; wherein each of L¹ and L² is independently —(CH₂)_(e)—, —(CH₂)_(e)O(CH₂)_(f)—, —(CH₂)_(e)S(CH₂)_(f)—, —(CH₂)_(e)NR¹¹(CH₂)_(f)—, —(CH₂)_(e)OCONR¹²(CH₂)_(f)—, —(CH₂)_(e)CONR¹³(CH₂)_(f)—, —(CH₂)_(e)NR¹⁴COO(CH₂)_(f)—, —(CH₂)_(e)NR¹⁵CO(CH₂)_(f)— or —(CH₂)_(e)NR¹⁶CONR¹⁷(CH₂)_(f)—; wherein each of R¹¹-R¹⁷ is independently hydrogen, methyl, or C₁-C₅ alkyl; and wherein each of e and f is independently an integer selected from the range of 0 to
 5. 20. (canceled)
 21. The emulsion of claim 19, wherein each of said semi-fluorinated block copolymers independently has the formula (FX4A) or (FX4B):


22. The emulsion of claim 19, wherein each of said semi-fluorinated block copolymers independently has the formula (FX5A) or (FX5B):

23-32. (canceled)
 33. The emulsion of claim 1, wherein said perhalogenated fluorous compound is selected from the group consisting of perfluorooctyl bromide, perfluorononyl bromide, perfluorodecyl bromide, perfluorodecalin, perfluorodichlorooctane, bis-perfluorobutyl ethylene and perfluoro(methyldecalin). 34-38. (canceled)
 39. The emulsion of claim 1, wherein said hydrophobic compound is a hydrophobic drug or an anesthetic drug.
 40. The emulsion of claim 1, wherein said hydrophobic compound is characterized by a solubility in water of equal to or less than 0.7 mM.
 41. The emulsion of claim 1, wherein said hydrophobic compound is a substituted or unsubstituted aromatic compound or a substituted or unsubstituted heteroaromatic compound.
 42. (canceled)
 43. The emulsion of claim 39, wherein said anesthetic drug is propofol or alfaxalone.
 44. (canceled)
 45. (canceled)
 46. The emulsion of claim 1, wherein the hydrophobic compound has a concentration selected from the range of 0.2 mg mL⁻¹ to 50 mg mL⁻¹, the perhalogenated fluorous compound is 5% to 20% by volume of said emulsion; and wherein the semi-fluorinated block copolymers have a concentration selected from the range of 10 mg mL⁻¹ to 50 mg mL⁻¹.
 47. (canceled)
 48. (canceled)
 49. The emulsion of claim 1, wherein said dispersed phase comprises a plurality of droplets dispersed in said continuous phase, wherein said droplets have an average diameter less than or equal to 400 nanometers. 50-52. (canceled)
 53. The emulsion of claim 1, wherein said droplets have a fluorophilic core comprising said fluorophilic blocks of said semi-fluorinated block copolymers; a hydrophilic exterior shell comprising said hydrophilic blocks of said semi-fluorinated block copolymers; and a hydrophobic intermediate shell comprising said hydrophobic blocks of said semi-fluorinated block copolymers. 54-58. (canceled)
 59. A method of delivering a therapeutic agent to a subject in need thereof, said method comprising the steps of: providing an emulsion comprising: an aqueous solution; semi-fluorinated block copolymers; wherein each of said semi-fluorinated block copolymers independently comprises a hydrophilic block, a hydrophobic block and a fluorophilic block; wherein said hydrophobic block of each of said semi-fluorinated block copolymers is provided between said fluorophilic block and said hydrophilic block; said therapeutic agent comprising a hydrophobic compound; and a perhalogenated fluorous compound; said emulsion comprising a continuous phase and a dispersed phase, wherein said continuous phase comprises said aqueous solution and said dispersed phase comprises said semi-fluorinated block copolymers, said therapeutic agent and said perhalogenated fluorous compound; and administering said emulsion to said subject, wherein said therapeutic agent is released from said emulsion, thereby delivering said therapeutic agent to said subject in need thereof.
 60. (canceled)
 61. The method of claim 59, wherein said hydrophobic compound is a hydrophobic drug or anesthetic drug.
 62. (canceled)
 63. The method of claim 62, wherein said hydrophobic drug is propofol or alfaxalone.
 64. The method of claim 59, wherein said step of administering said emulsion provides for controlled release of said hydrophobic compound from said emulsion.
 65. The method of claim 59, wherein said step of administering said emulsion is carried out via intraveneous injection.
 66. The method of claim 59, wherein a volume of said emulsion is less than or equal to 500 mL is administered to said subject.
 67. The method of claim 59, wherein said emulsion is delivered to said subject at a rate less than or equal to 100 mL per minute.
 68. A method of making an emulsion, said method comprising the steps of: providing a therapeutic formulation comprising: an aqueous solution; semi-fluorinated block copolymers; wherein each of said semi-fluorinated block copolymers independently comprises a hydrophilic block, a hydrophobic block and a fluorophilic block; wherein said hydrophobic block of each of said semi-fluorinated block copolymers is provided between said fluorophilic block and said hydrophilic block; said therapeutic agent comprising a hydrophobic compound; and a perhalogenated fluorous compound; and emulsifying said therapeutic formulation, thereby making an emulsion comprising a continuous phase and a dispersed phase, wherein said continuous phase comprises said aqueous solution and said dispersed phase comprises said semi-fluorinated block copolymers, said therapeutic agent and said perhalogenated fluorous compound.
 69. (canceled)
 70. The method of claim 68, wherein said step of emulsifying said therapeutic formulation comprises the steps of: adding said hydrophobic compound and said perhalogenated fluorous compound to said aqueous solution having said semi-fluorinated block copolymers therein, thereby generating a mixture; and homogenizing said mixture, thereby generating said emulsion.
 71. The method of claim 68 further comprising the step of lowering a temperature of said mixture during said step of homogenizing said mixture.
 72. (canceled) 